Aleppo (Syria) (AFP) - UN chief Ban Ki-moon said Saturday he was "appalled by the chilling military escalation" in Syria's battleground city of Aleppo where residents cowered indoors as air strikes toppled buildings and killed at least 45 civilians.

The Security Council was set to meet Sunday to discuss the upsurge in violence since the Syrian army announced an offensive to retake the rebel-held east of the devastated city.

Nearly two million civilians were left without water in Aleppo after regime bombardment damaged a pumping station and rebels shut down another in retaliation, the UN said.

Ban warned the use of bunker buster bombs and other advanced munitions against civilians may amount to war crimes, after the army Thursday launched the offensive backed by Russian air raids that has cost around 100 lives.

Top EU officials said that the attacks on civilians amount to a "breach of international humanitarian law," and called for intensified peace efforts.

Washington and leading European powers said Saturday that "the burden is on Russia... to salvage diplomatic efforts to restore a cessation of hostilities."

A week-long ceasefire agreed between the United States and Russia ended on Monday and efforts to revive the truce failed.

That same day, an aid convoy was hit by an air strike that US officials have said was carried out by Russian planes, although Moscow has denied responsibility.

- 'Cease bombing women and children' -

US Secretary of State John Kerry, who failed in talks with Russian counterpart Sergei Lavrov to revive the ceasefire, earlier said: "What is happening in Aleppo today is unacceptable. It is beyond the pale."

"If people are serious about wanting a peaceful outcome... they should cease and desist bombing innocent women and children, cease cutting off water and laying siege in mediaeval terms to an entire community," he said.

Kerry had harsh words for Moscow's involvement in the conflict, in comments at a meeting with his European counterparts.

"Russia needs to set an example, not a precedent -– an unacceptable precedent, I might add, for the entire world," he said.

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Syria's regime said it was confident of victory, with Foreign Minister Walid Muallem telling the UN General Assembly that the army and its allies were making "great strides" in the conflict.

He said a US-led coalition air strike that killed at least 62 Syrian soldiers on September 17 was intentional "and not an error, even if the United States claims otherwise".

Rebel-held eastern districts of Aleppo came under intense air and artillery fire for a fifth night on Friday ahead of an anticipated ground offensive by the army to recapture the whole of the divided city.

Muallem told the UN: "Our belief in victory is even greater now that the Syrian Arab Army is making great strides in its war against terrorism, with the support of the true friends of the Syrian people," singling out Russia, Iran and Lebanon's Shiite militant group Hezbollah.

Saturday's death toll of 45 in Aleppo city was expected to rise because people remained trapped in the rubble, said the Syrian Observatory for Human Rights, a Britain-based monitoring group.

It said another seven people were killed elsewhere in Aleppo province on Saturday.

"We were home when a missile crashed into our road," said one resident of the Bab al-Nayrab district who gave his name as Nizar.

"Half of the building just caved in and our baby was hit on the head. He died on the spot," Nizar said, the body of his son on the ground wrapped in a blanket.

- Massive destruction -

Seven people were killed in a strike as they queued to buy yoghurt at a market in the Bustan al-Qasr district on the front line dividing the government-held west from the rebel-held east of the city.

The attack left a pool of blood and body parts strewn across the site, said an AFP correspondent on the scene.

Medics said they were carrying out many amputations to try to save the wounded, while supplies of blood and IV drips were running out.

On Friday, at least 47 people were killed in heavy bombing, among them seven children, the Observatory said.

There was massive destruction in several neighbourhoods, including Al-Kalasseh and Bustan al-Qasr, where some streets were almost erased by the bombardment.

Residents and activists said one type of bomb had produced earthquake-like tremors upon impact, razing buildings right down to their basements where many residents desperately seek safety during attacks.

Further south in the central city of Homs, a convoy of 36 aid trucks reached the rebel-held district of Waer, the International Committee of the Red Cross said.

The denial of access to food, water and medicines has been used repeatedly as a weapon by all sides in the five-year war which has cost more than 300,000 lives and displaced over half the population.

The approximately 250,000 people in east Aleppo have been under near-continuous siege since government troops encircled the area in mid-July.</s>(CNN) Syrian forces pounded rebel-held eastern Aleppo on Sunday, killing at least 85 people and wounding more than 300 others, an activist group reported. The bombardment destroyed residential centers, overwhelmed hospitals and angered diplomats meeting at the United Nations.

"Everyone in Aleppo is depressed," an activist on the ground told CNN.

Can Russia and US reach common ground on Syria?

Can Russia and US reach common ground on Syria? 01:53

Can Russia and US reach common ground on Syria?

"They don't know what they have done to become targets for warplanes. Fear is clear in the eyes of anyone you see walking the streets of Aleppo. Yesterday I saw a woman walking on the street and crying , no clear reason, just crying."

Hundreds of airstrikes have pummeled the city, home to more than 250,000 people, since the Syrian government, backed by Russia, announced a renewed, "comprehensive" offensive Thursday following the collapse of a short-lived ceasefire.

Sunday's death toll marked an increase in casualties, according to the Aleppo Media Center (AMC), an opposition-affiliated group of activists that works to document the conflict.

Activists say rescue operations are difficult in Aleppo because of the constant presence of jets in the sky, and that hospitals are facing severe shortages of medicine, blood and supplies.

The activist who recounted Aleppo residents' fears said that in one hospital, where a fellow activist was being treated, 40 people lay strewn on the floor because there were no beds.

Wounded people are dying because health services are overstretched and providers don't have the ability or capacity to treat them, the activist said. Due to a lack of supplies, hospitals are performing amputations to keep some people alive.

Only 20 doctors remain in eastern Aleppo, the activist added.

The renewed attacks, which include barrel bombs, come as the U.N. Security Council held a crisis meeting Sunday to discuss the Syrian government's offensive on Aleppo. At the meeting, diplomats exchanged fiery words,

The US Ambassador to the United Nations accused Russia of engaging in barbarism in Syria.

"What Russia is sponsoring and doing is not counterterrorism, it is barbarism," Samantha Power told the Security Council.

"Instead of pursuing peace, Russia and Assad make war. Instead of helping get life-saving aid to civilians, Russia and Assad are bombing the humanitarian convoys, hospitals and first responders who are trying desperately to keep people alive," Power said.

Russian Ambassador to the UN Vitaly Churkin said the US-led coalition's support for rebels was hampering humanitarian efforts.

"The humanitarian situation in Aleppo could have been normalized in August but that was not done, it was not allowed because the armed groups prevented that," he said.

The United States, Britain and France requested the session in the wake of the regime's military push to retake rebel-held parts of eastern Aleppo.

Syria's ambassador to the United Nations, Bashar Jaafari, told the Security Council that his government plans to retake all of the territory lost to rebels, including the city of Aleppo.

UK Foreign Secretary Boris Johnson said Sunday that Russia is guilty of protracting the Syrian war and making it "far more hideous."

U.N. Secretary-General Ban Ki-moon also said that the Syrian government's use of airstrikes, incendiary weapons and bunker-buster bombs in densely populated areas may amount to war crimes.

Syrian government troops and supporting militia on Saturday made their first major ground advance of the assault on Aleppo, seizing control of the Handarat Palestinian refugee camp on the city's northeastern outskirts, while warplanes bombarded the east, according to the state-run Syrian Arab News Agency.

Rebels then launched a counter offensive to try to retake the area, according to the UK-based Syrian Observatory for Human Rights.

Syria's military declared the ceasefire over on Monday, after a strike by US-led coalition warplanes on a Syrian army post killed dozens of troops.

The US military did not dispute the strike, but characterized it as "unintentional" and relayed its "regret" to Syria through Russia, saying the intended target had been ISIS.

Shortly after the ceasefire ended, a UN-Syrian Arab Red Crescent aid convoy was hit in an airstrike, killing about 20 people. US officials blamed Russia, while Moscow denied that Russian or Syrian warplanes were responsible.</s>(CNN) Syrian forces pounded rebel-held eastern Aleppo on Sunday, killing at least 85 people and wounding more than 300 others, an activist group reported. The bombardment destroyed residential centers, overwhelmed hospitals and angered diplomats meeting at the United Nations.

"Everyone in Aleppo is depressed," an activist on the ground told CNN.

Can Russia and US reach common ground on Syria?

Can Russia and US reach common ground on Syria? 01:53

Can Russia and US reach common ground on Syria?

"They don't know what they have done to become targets for warplanes. Fear is clear in the eyes of anyone you see walking the streets of Aleppo. Yesterday I saw a woman walking on the street and crying , no clear reason, just crying."

Hundreds of airstrikes have pummeled the city, home to more than 250,000 people, since the Syrian government, backed by Russia, announced a renewed, "comprehensive" offensive Thursday following the collapse of a short-lived ceasefire.

Sunday's death toll marked an increase in casualties, according to the Aleppo Media Center (AMC), an opposition-affiliated group of activists that works to document the conflict.

Activists say rescue operations are difficult in Aleppo because of the constant presence of jets in the sky, and that hospitals are facing severe shortages of medicine, blood and supplies.

The activist who recounted Aleppo residents' fears said that in one hospital, where a fellow activist was being treated, 40 people lay strewn on the floor because there were no beds.

Wounded people are dying because health services are overstretched and providers don't have the ability or capacity to treat them, the activist said. Due to a lack of supplies, hospitals are performing amputations to keep some people alive.

Only 20 doctors remain in eastern Aleppo, the activist added.

The renewed attacks, which include barrel bombs, come as the U.N. Security Council held a crisis meeting Sunday to discuss the Syrian government's offensive on Aleppo. At the meeting, diplomats exchanged fiery words,

The US Ambassador to the United Nations accused Russia of engaging in barbarism in Syria.

"What Russia is sponsoring and doing is not counterterrorism, it is barbarism," Samantha Power told the Security Council.

"Instead of pursuing peace, Russia and Assad make war. Instead of helping get life-saving aid to civilians, Russia and Assad are bombing the humanitarian convoys, hospitals and first responders who are trying desperately to keep people alive," Power said.

Russian Ambassador to the UN Vitaly Churkin said the US-led coalition's support for rebels was hampering humanitarian efforts.

"The humanitarian situation in Aleppo could have been normalized in August but that was not done, it was not allowed because the armed groups prevented that," he said.

The United States, Britain and France requested the session in the wake of the regime's military push to retake rebel-held parts of eastern Aleppo.

Syria's ambassador to the United Nations, Bashar Jaafari, told the Security Council that his government plans to retake all of the territory lost to rebels, including the city of Aleppo.

UK Foreign Secretary Boris Johnson said Sunday that Russia is guilty of protracting the Syrian war and making it "far more hideous."

U.N. Secretary-General Ban Ki-moon also said that the Syrian government's use of airstrikes, incendiary weapons and bunker-buster bombs in densely populated areas may amount to war crimes.

Syrian government troops and supporting militia on Saturday made their first major ground advance of the assault on Aleppo, seizing control of the Handarat Palestinian refugee camp on the city's northeastern outskirts, while warplanes bombarded the east, according to the state-run Syrian Arab News Agency.

Rebels then launched a counter offensive to try to retake the area, according to the UK-based Syrian Observatory for Human Rights.

Syria's military declared the ceasefire over on Monday, after a strike by US-led coalition warplanes on a Syrian army post killed dozens of troops.

The US military did not dispute the strike, but characterized it as "unintentional" and relayed its "regret" to Syria through Russia, saying the intended target had been ISIS.

Shortly after the ceasefire ended, a UN-Syrian Arab Red Crescent aid convoy was hit in an airstrike, killing about 20 people. US officials blamed Russia, while Moscow denied that Russian or Syrian warplanes were responsible.</s>Russia accused of ‘barbarism’ at emergency UNSC meet for aiding Damascus in air strikes

Residents of Syria’s battered city of Aleppo faced worsening food and medical shortages on Monday as Syrian and Russian war-planes again pounded rebel-held areas in defiance of international concern.

A fresh wave of intensive air strikes hit the city’s opposition-controlled east from dawn on Monday, an AFP correspondent in the city said, on the morning after Moscow and Damascus were repeatedly accused of war crimes at the UN Security Council.

The emergency council meeting, called by Britain, France and the United States, saw Russia accused of “barbarism” over the worsening carnage in Aleppo.

Yet, the worst violence to hit the divided city in years continued on Monday and residents warned that stores of food and vital medical supplies were dwindling to nothing. The strikes from dawn on Monday were particularly heavy on two rebel-held districts, Al-Mashhad and Sayf al-Dawla, and sparked large fires, the AFP correspondent said. The Syrian Observatory for Human Rights, a Britain-based monitor, said “dozens of raids” had hit districts of east Aleppo after midnight on Sunday, with many wounded and at least two civilians killed.

It was the fourth day of intense air raids on the city since a defiant Syrian regime launched a new assault vowing to retake all of Aleppo following the collapse early last week of a short-lived ceasefire brokered by Russia and the United States.

The Observatory said Monday that at least 128 people, nearly all civilians, had been killed in Syrian and Russian raids on eastern Aleppo since late Thursday.

A Syrian military source told AFP regime forces had no intention of letting up on rebel-held areas. “The air force will bomb any terrorist movements, this is an irreversible decision,” the source said, reiterating that the regime’s goal was to “recapture all regions of Syria” outside its control.

With Aleppo back under siege since regime forces again fully surrounded the city in early September, residents were having to deal with food shortages and sky-rocketing prices as well as intensifying violence.

Several charity kitchens that had distributed food in eastern districts were no longer operating due to the danger of air strikes.

Water supplies also remained cut off to many areas after pumping stations were damaged at the weekend.

At the Security Council meeting, U.S. Ambassador Samantha Power voiced strong criticism of Russia’s support for President Bashar Al-Assad’s regime. “What Russia is sponsoring and doing is not counter-terrorism. It is barbarism,” she said.

Russia launched air strikes in support of Mr. Assad last September, helping regime forces to regain ground lost to a wide range of opposition forces. UN envoys raised deep concern over the use of arms including bunker-busting bombs in the Aleppo strikes. ”It is difficult to deny that Russia is partnering with the Syrian regime to carry out war crimes,” said British Ambassador Matthew Rycroft. UN Secretary General Ban Ki-moon has also warned the use of advanced weaponry against civilians could amount to war crimes.</s>(CNN) Syrian forces pounded rebel-held eastern Aleppo on Sunday, killing at least 85 people and wounding more than 300 others, an activist group reported. The bombardment destroyed residential centers, overwhelmed hospitals and angered diplomats meeting at the United Nations.

"Everyone in Aleppo is depressed," an activist on the ground told CNN.

Can Russia and US reach common ground on Syria?

Can Russia and US reach common ground on Syria? 01:53

Can Russia and US reach common ground on Syria?

"They don't know what they have done to become targets for warplanes. Fear is clear in the eyes of anyone you see walking the streets of Aleppo. Yesterday I saw a woman walking on the street and crying , no clear reason, just crying."

Hundreds of airstrikes have pummeled the city, home to more than 250,000 people, since the Syrian government, backed by Russia, announced a renewed, "comprehensive" offensive Thursday following the collapse of a short-lived ceasefire.

Sunday's death toll marked an increase in casualties, according to the Aleppo Media Center (AMC), an opposition-affiliated group of activists that works to document the conflict.

Activists say rescue operations are difficult in Aleppo because of the constant presence of jets in the sky, and that hospitals are facing severe shortages of medicine, blood and supplies.

The activist who recounted Aleppo residents' fears said that in one hospital, where a fellow activist was being treated, 40 people lay strewn on the floor because there were no beds.

Wounded people are dying because health services are overstretched and providers don't have the ability or capacity to treat them, the activist said. Due to a lack of supplies, hospitals are performing amputations to keep some people alive.

Only 20 doctors remain in eastern Aleppo, the activist added.

The renewed attacks, which include barrel bombs, come as the U.N. Security Council held a crisis meeting Sunday to discuss the Syrian government's offensive on Aleppo. At the meeting, diplomats exchanged fiery words,

The US Ambassador to the United Nations accused Russia of engaging in barbarism in Syria.

"What Russia is sponsoring and doing is not counterterrorism, it is barbarism," Samantha Power told the Security Council.

"Instead of pursuing peace, Russia and Assad make war. Instead of helping get life-saving aid to civilians, Russia and Assad are bombing the humanitarian convoys, hospitals and first responders who are trying desperately to keep people alive," Power said.

Russian Ambassador to the UN Vitaly Churkin said the US-led coalition's support for rebels was hampering humanitarian efforts.

"The humanitarian situation in Aleppo could have been normalized in August but that was not done, it was not allowed because the armed groups prevented that," he said.

The United States, Britain and France requested the session in the wake of the regime's military push to retake rebel-held parts of eastern Aleppo.

Syria's ambassador to the United Nations, Bashar Jaafari, told the Security Council that his government plans to retake all of the territory lost to rebels, including the city of Aleppo.

UK Foreign Secretary Boris Johnson said Sunday that Russia is guilty of protracting the Syrian war and making it "far more hideous."

U.N. Secretary-General Ban Ki-moon also said that the Syrian government's use of airstrikes, incendiary weapons and bunker-buster bombs in densely populated areas may amount to war crimes.

Syrian government troops and supporting militia on Saturday made their first major ground advance of the assault on Aleppo, seizing control of the Handarat Palestinian refugee camp on the city's northeastern outskirts, while warplanes bombarded the east, according to the state-run Syrian Arab News Agency.

Rebels then launched a counter offensive to try to retake the area, according to the UK-based Syrian Observatory for Human Rights.

Syria's military declared the ceasefire over on Monday, after a strike by US-led coalition warplanes on a Syrian army post killed dozens of troops.

The US military did not dispute the strike, but characterized it as "unintentional" and relayed its "regret" to Syria through Russia, saying the intended target had been ISIS.

Shortly after the ceasefire ended, a UN-Syrian Arab Red Crescent aid convoy was hit in an airstrike, killing about 20 people. US officials blamed Russia, while Moscow denied that Russian or Syrian warplanes were responsible.</s>Beirut (AP) — At least 26 civilians were killed in fresh government airstrikes on the contested city of Aleppo, Syrian activists said Sunday, as the United Nations Security Council convened an emergency meeting on the spiraling violence in Syria.

At the start of that meeting the U.N.’s top envoy to Syria accused the government of unleashing “unprecedented military violence” against civilians in Aleppo.

Staffan de Mistura said Syria’s declaration of a military offensive to retake rebel-held eastern Aleppo has led to one of the worst weeks of the 5 1/2-year war with dozens of airstrikes against residential areas and buildings causing scores of civilian deaths.

He said the offensive targeting civilians with sophisticated weapons including incendiary devices may amount to war crimes.

Medical workers and local officials reported airstrikes on neighborhoods throughout Aleppo’s rebel-held eastern districts as an announced government offensive entered its fourth day.

The Britain-based Syrian Observatory for Human Rights reported 26 civilians had been killed by 7:30 p.m. and said it expects the toll to rise.

Ibrahim Alhaj of the Syrian Civil Defense search and rescue outfit said hospitals and rescuers have documented the deaths of 43 people so far.

Hospitals are overwhelmed with casualties and medical workers are expecting many of the wounded to die from a lack of treatment, according to Mohammad Zein Khandaqani, a member of the Medical Council, which oversees medical affairs in the city’s opposition quarters.

“I’ve never seen so many people dying in once place,” he said from a hospital in the city. “It’s terrifying today. In less than one hour the Russian planes have killed more than 50 people and injured more than 200.”

The Observatory, which relies on a network of contacts inside Syria, said earlier in the day that 213 civilians have been killed by airstrikes and shelling on opposition areas in and around Aleppo since a U.S.-Russian brokered cease-fire collapsed Monday evening.

De Mistura, at the Security Council meeting, warned that if the Syrian government is intent on taking Aleppo, it is going to be “a grinding” a street-by-street fight where all the infrastructure in the city will be destroyed, but it won’t lead to victory.

“A so-called military solution is impossible, including in Aleppo,” he stressed.

He urged the United States and Russia to go “that extra mile” and save the Sept. 9 cessation of hostilities agreement “at the 11th hour.”

On the sidelines of the meeting, U.N. Secretary-General Ban Ki-moon urged the Security Council to force a halt to the hostilities in Aleppo, and he condemned Russia and the Syrian government’s alleged use of bunker busting bombs, which are designed to penetrate underground facilities.

“Let us remember: The fighting has forced hospitals and schools to operate in basements. These bombs are not busting bunkers, they are demolishing ordinary people looking for any last refuge of safety,” Ban said.

“International law is clear: The systematic use of indiscriminate weapons in densely populated areas is a war crime,” he said.

Prior to the start of the U.N. meeting, British Foreign Secretary Boris Johnson said Russia should be investigated for war crimes following a Monday attack on a Syrian aid convoy that claimed 20 lives.

Johnson said that Russia’s air force may have deliberately targeted the civilian convoy on Sept. 19. Russia denies involvement and instead suggests Syrian rebels or a U.S. drone were responsible.

France’s Foreign Minister Jean-Marc Ayrault said Russia and Iran will be guilty of war crimes if they don’t pressure Syrian President Bashar Assad to stop escalating violence.

Ayrault said the emergency Security Council meeting Sunday is a “moment of truth” for the U.N.

The meeting was requested by the United States, Britain, and France, as pro-government forces extend their bombardment of the contested city of Aleppo. They are widely believed to be accompanied by Russian air strikes.

Rebels meanwhile shelled Masyaf, a government stronghold near the central city of Hama, for the second day in a row, according to the Observatory.

Masyaf is home to a large number of Alawites, members of President Bashar Assad’s sect. Assad has rallied Syria’s minorities behind his government behind fears of the Sunni-dominated rebellion.

The U.S., Britain, and France are aligned on the Security Council against Russia and China, which back Assad in the country’s protracted war, now in its sixth year.

But a broad coalition of Syrian rebels denounced international negotiations for peace as “meaningless,” earlier Sunday.

The statement released jointly by 33 factions called on the government and Russian forces to halt airstrikes and lift sieges on opposition areas. The U.N. estimates 600,000 Syrians are trapped in various sieges enforced by the government, rebels, and the Islamic State group across the country.

“Negotiations under the present conditions are no longer useful and are meaningless,” the statement said.

The factions said they would not accept to have Russia mediate any negotiations, calling it a “partner to the regime in the crimes against our people.”

The statement was signed by some of the largest factions from across Syria but did not include the powerful, ultraconservative Ahrar al-Sham nor the al-Qaida-linked Fatah Sham Front.

Efforts to revive the truce have floundered. An airstrike destroyed a U.N.-backed humanitarian convoy Monday inside opposition territory shortly after the Syrian military announced the agreement had expired. The U.N. says the attack could amount to a war crime if proven deliberate, though it has not assigned responsibility yet. The U.S. says it believes Russian jets were behind the strikes.

Meanwhile, a set of four towns, two besieged by government forces and two by rebels, were reached by aid convoys for the first time in nearly six months, the International Committee for the Red Cross announced.

The organization said Sunday it had reached 60,000 residents trapped in the towns of Madaya, Zabadani, Foua, and Kafraya.

Government forces and rebels have so far blocked the U.N. from establishing regular aid access to besieged areas in Syria. The U.N. estimates 600,000 Syrians are trapped in different sieges.</s>At least 26 civilians were killed in fresh government airstrikes on the contested city of Aleppo, Syrian activists said Sunday, as the United Nations Security Council convened an emergency meeting on the spiraling violence in Syria but failed to take any action because of deep divisions between Russia and the Western powers.

The United States, Britain and France, who called the emergency meeting, heaped blame on Moscow for supporting the Syrian offensive which U.N. envoy Staffan de Mistura called one of the worst of the 5 1/2-year war.

When Syria's U.N. Ambassador Bashar Ja'afari was called to speak in the council, the ambassadors of the three Western powers walked out in protest.

They had demanded a halt to the Aleppo offensive and immediate council action, and their walkout demonstrated anger and frustration not only at Damascus but at Russia for backing close ally Bashar Assad's military campaign while talking about reviving a cessation of hostilities.

"What Russia is sponsoring and doing is not counter-terrorism, it's barbarism," said U.S. Ambassador Samantha Power. "It's apocalyptic what is being done in eastern Aleppo."

As the government offensive entered its fourth day on Sunday, medical workers and local officials reported airstrikes on neighborhoods throughout Aleppo's rebel-held eastern districts.

The Britain-based Syrian Observatory for Human Rights reported 26 civilians had been killed by 7:30 p.m. and said it expects the toll to rise. Ibrahim Alhaj of the Syrian Civil Defense search and rescue outfit gave a higher toll, saying hospitals and rescuers had documented the deaths of 43 people so far on Sunday.</s>The U.S. accused Moscow of “barbarism” over the worsening carnage in Aleppo, as Syrian and Russian warplanes pounded the city in one of the heaviest bombing raids of the five-year war.

At an emergency meeting of the U.N. Security Council to demand Russia rein in its ally, Syrian President Bashar al-Assad, and halt intense airstrikes, Moscow and Damascus were repeatedly accused of war crimes.

“What Russia is sponsoring and doing is not counterterrorism. It is barbarism,” U.S. Ambassador Samantha Power said at the Sunday session.

Some 124 people, mostly civilians, have died since bunker-busting bombs and sophisticated weaponry were unleashed on residential areas in rebel-held eastern Aleppo after the army Thursday launched an operation to take it.

“It is difficult to deny that Russia is partnering with the Syrian regime to carry out war crimes,” said British Ambassador Matthew Rycroft, adding that the high-tech weaponry had inflicted “a new hell” on war-weary Syrians.

UN Secretary-General Ban Ki-moon has also warned the use of advanced weaponry against civilians could amount to war crimes, and French Ambassador Francois Delattre said the atrocities must not go unpunished.

Britain, France and the United States had called for the urgent talks after days of intense diplomatic efforts to salvage a U.S.-Russian cease-fire deal ended in failure at the weekend.

Ban called on world powers to “work harder for an end to the nightmare” in Syria that has left more than 300,000 people dead and driven millions from their homes.

To protest the attacks in Aleppo, the US, French and British ambassadors walked out of the Security Council chamber as the Syrian ambassador delivered his remarks.

Russian Ambassador Vitaly Churkin conceded that the surge in violence over the past days meant that “bringing a peace is almost an impossible task now.”

Churkin again laid blame for the failed diplomacy with the United States, accusing Washington of being unable to convince armed opposition groups that it backs on the ground to distance themselves from the al-Qaida-linked Nusra Front and abide by the cease-fire.

A U.S.-Russian cease-fire deal that would have charted a way forward towards peace talks was broken by the “sabotage by the moderate opposition,” he asserted.

Churkin however said that reviving the cease-fire was still a goal that Moscow could pursue if it was part of a “collective” effort on all sides.

Despite the recriminations, U.N. envoy Staffan de Mistura said a “tiny window of opportunity … still exists” for Russia and the United States to help Syria.

He appealed for renewed efforts to allow Syria to “step away from the brink of more years of bloody conflict which risks to become even worse.”

Residents said cluster bombs rained down on Saturday night on eastern parts of the city, where an estimated 250,000 people are living under a government siege.

At least 19 children were among those killed in the assault, which has included missile strikes, barrel bomb attacks and artillery fire, the Syrian Observatory for Human Rights said.

“All night long they were dropping cluster bombs. I couldn’t sleep until four in the morning,” said 62-year-old Ahmed Hajar, who was out looking for bread in the al-Kalasseh neighborhood.

In the nearby neighborhood of Bab al-Nayrab, 30-year-old Imad Habush was baking bread in a small wood-burning oven outside his house.

“None of the bakeries are open any more because of the bombing and the shortages of fuel and flour, so people have started making their own bread,” he said.

“I don’t know why the regime is bombing us in this barbaric way. We’re civilians here. We’re not carrying weapons, and we’re besieged. We have no way to escape.”

Air strikes were continuing on the eastern neighborhoods on Sunday, the Observatory said, with at least 25 civilians, including two children, killed since dawn.

Once Syria’s economic powerhouse, Aleppo has been ravaged by war and roughly divided since mid-2012 between government control in the west and rebel control in the east.

The eastern portion of the city has been under near-continuous siege since mid-July, causing food and fuel shortages.

Syria’s foreign minister said Saturday that his government was confident of “victory” with support from “true friends” including Russia, Iran, and Lebanon’s Shiite militant group Hezbollah.

U.S. military chief Joe Dunford said last week that Washington was considering arming Syrian Kurdish forces ahead of an offensive to retake the Islamic State group’s stronghold of Raqa.

Turkey’s foreign minister told France24 Sunday that the plan was “unacceptable.”

Ankara, a NATO member and member of the U.S.-led coalition against the Islamic State group, launched an unprecedented ground operation in Syria last month, sending dozens of tanks to back pro-Turkish rebels fighting Kurdish militias as well as jihadists.
The United States, United Kingdom, and France seek a meeting of the United Nations Security Council to discuss the declining security situation in Aleppo.