Here's a summary of the main events today: 
 
 Syria 
 
 • Syrian rebels say they captured an air defence base with a cache of missiles outside Damascus. Videos posted on the internet purport to show a government helicopter being shot down in the same area. 
 
 • The central city of Homs has been subjected to its most severe bombardment in five months, the BBC reports citing activists. Aircraft and artillery targeted the neighbourhood of Khaldiya, the Syrian Observatory for Human Rights said. 
 
 • A UN security council statement has condemned Syria's mortar attack in Turkey, urged restraint, but on Russia's insistence, removed a reference to the incident being a "threat to international peace and security." A second statement has condemned the bombings in Aleppo that reportedly killed 48 people earlier this week. 
 
 • The Syrian regime has ordered its military to stay 10km away from the Turkish border, according to Turkish news website. 
 
 • Rebels have again threatened to execute Iran hostages in a bid to stop government shelling, according to an update from Ausama Monajed a leading member of the opposition Syrian National Council. Video from the al-Baraa brigade gave the Syrian regime a 48-hour deadline to end the shelling and release all detainees before they execute 45 Iranians who were captured in Damascus in August. 
 
 • Human Rights Watch has called for the release of a prominent human rights lawyer who was abducted on Tuesday while driving to his office. Khalil Maatouk, executive director of the Syrian Center for Legal Studies and Research, and his friend Mohamed Zaza, haven't been seen since then. 
 
 Jordan 
 
 • Thousands of people have gathered in the capital Amman for a pro-reform rally. The demonstration signalled the failure of King Abdullah's attempt to quell public anger ahead of the rally by dissolving parliament. 
 
 Iran 
 
 • Iran will defeat an enemy "conspiracy" against its foreign currency and gold markets, an adviser to the country's supreme leader said on Friday, following violent protests that closed Tehran's grand bazaar. "Iran is overcoming the psychological war and conspiracy that the enemy has brought to the currency and gold market and this war is constantly fluctuating," Gholam Ali Haddad Adel, an adviser, was quoted by the semi-official Fars news agency as saying. 
 
 Libya 
 
 • Tension continues around Bani Walid in Libya, with reports of a militia attack overnight. The Libyan army is reported to be poised to attack the town. 
 
 Morocco 
 
 • Morocco has withdrawn accreditation from a journalist working for the French news agency, AFP, after he wrote an article linking the palace to a political party competing in by-elections. ||||| Media playback is unsupported on your device Media caption The BBC's Wyre Davies says government forces have launched a co-ordinated attack on Aleppo 
 
 Fighter jets have bombed eastern areas of Syria's second city Aleppo, a BBC reporter near the city says. 
 
 The attack, which followed an artillery barrage, is seen as a significant escalation in the conflict. 
 
 Rebels launched an offensive against Aleppo at the weekend in an attempt to wrest the city from government forces. 
 
 US Secretary of State Hillary Clinton says territorial gains made by the rebels will eventually result in a "safe haven" inside Syria. 
 
 "We have to work closely with the opposition, because more and more territory is being taken," she told reporters in Washington. That would become a safe haven which would provide a base for further action by the opposition, she said. 
 
 At the scene The military's response today marked a sharp escalation in this battle. Helicopter gunships spun through the skies throughout the day. Sustained artillery and mortar rounds pounded restive neighbourhoods. But it was what happened late in the afternoon that underlined the grave risk to the government of losing ground in what is Syria's largest city and its economic capital. First came an unmistakeable sound that has so far been absent in this conflict - the roar of fighter jets. What appeared to be Russian-made MiG planes arced through the sky. We watched as they dropped in, bombing and strafing rebel positions. Dead and wounded civilians and fighters were taken to hospitals and makeshift clinics as the human cost of this conflict continues to grow. Warplanes hit Aleppo 
 
 Mrs Clinton said the pace of events was accelerating inside Syria and called on the opposition to be prepared for a transition of power, adding that it was not yet too late for President Assad himself to prepare for such a handover. 
 
 In one of the deadliest incidents of the day, opposition activists reported that at least 20 worshippers were killed as they went into a mosque in a village close to the city of Hama. 
 
 Troops and militia loyal to President Assad left a roadblock and opened fire on the men who were arriving for evening prayers in Shariaa, one activist told Reuters news agency. 
 
 Foreign journalists work under intense restrictions in Syria so reports by both sides are hard to verify. 
 
 Police besieged 
 
 Earlier in Aleppo, government forces launched what correspondents described as a co-ordinated attack on the Tariq al-Bab area in the east of the city late on Tuesday afternoon, first with a 10-minute barrage of 30 shells and then with bombing runs from fixed-wing jets. 
 
 It was thought to be the first time that Syrian fighter planes had been used for bombing urban targets during the conflict, as the government attempted to take back districts of Syria's commercial centre seized by the rebels. 
 
 There are reports of dozens of casualties and widespread damage. The BBC's Ian Pannell, on the outskirts of Aleppo, says civilians and fighters are among the dead and wounded. 
 
 Helicopter gunships have been involved in the clashes in the city throughout the day, he says. 
 
 Fierce fighting has been reported close to the historic Old City. A French correspondent there has spoken of rebels besieging a police headquarters close to the walls of the Old City, which is a world heritage site. 
 
 Government forces have already regained control of most areas of Damascus that were captured by rebels last week. Opposition activists report renewed raids by troops in the Tadamon, Qadam and Assali areas of the city. 
 
 State television has broadcast video of soldiers apparently securing and checking heavily shelled suburbs in the south of the capital. 
 
 The battle for Aleppo, Syria's most populous city, appears to have spread to much of the city, with rebels claiming control of several areas. 
 
 State forces appear to have focused their counter-attack on the Sakhour area to the east of the city centre, where rebels destroyed several tanks on Monday, the BBC's Jim Muir reports from neighbouring Lebanon. 
 
 'Border shelling' 
 
 The violence on Tuesday claimed the lives of more than 100 people in Syria, according to the opposition Local Co-ordination Committees, including 20 in Aleppo. 
 
 Image caption The shell of a burnt-out bus is seen in the Qabun district of Damascus. In pictures: Syria conflict 
 
 Thirteen people died in a revolt in Aleppo prison, activists said, when security forces reportedly opened fire and used tear gas on detainees. 
 
 Explosions and fires have also been reported from the jail in Homs where a similar mutiny took place. 
 
 Unverified reports said hundreds of refugees had become caught up in violence while trying to flee the country across its eastern border with Iraq. 
 
 Three people were wounded when Syrian forces shelled the Syrian side of the Boukamal crossing on the Euphrates river, where a crowd of Iraqis and Syrians were waiting to leave, a source has told the BBC. 
 
 The deteriorating security situation has prompted 10,000 Iraqi refugees to leave Syria in less than a week, according to the UN refugee agency. 
 
 Elsewhere, 10 people were reported killed when a shell hit their car near Hama and a family was said to have died during a bombardment of Deraa in southern Syria. 
 
 Chemical threat 
 
 As the battle for control of Syria's biggest cities spreads, international concern about Syria's chemical weapons stockpile has spread to its ally, Russia. 
 
 The US and the UN have already issued a warning to Damascus, after a Syrian spokesman said its weapons would never be used internally but could be deployed against "external aggression". 
 
 Russia's foreign ministry said on Tuesday that it "proceeds from the assumption that the Syrian authorities will continue to rigorously abide by their international obligations". 
 
 In other developments
– Assad's forces continue to pound Aleppo today, with state TV announcing that the regime is "cleansing the terrorist filth" from the country. Reuters reports that tanks are shelling the city as a helicopter sprays the rebels with machine-gun fire, and a correspondent there reported violent street fighting in the Salaheddine district. But things may be poised to get worse, with Reuters and CNN both hearing from rebels who say two large columns of government troops are on the march toward the city. "We know they are planning to attack using tanks and aircraft, shooting at us for three to four days and they plan to take the city," says one commander who expects the attack to come "within days." In other Syria news: The AP reports that the government yesterday claimed it was now in full control of all districts in Damascus after purging one of the last rebel-held areas. But several residents reported hearing loud explosions and gunfire from several districts of the capital throughout the night. Syria's first man in space today fled to Turkey and joined opposition forces there, reports the AP. It was Mohammed Ahmed Faris' fourth attempt to defect, says Turkey. A pan-Arab TV station aired a video today purporting to show Syrian rebels guarding a group of 48 Iranians abducted a day earlier and promising more attacks on Iranian targets. Armed men in the video claim the Iranians were on a "reconnaissance mission" in Damascus at the time they were abducted. Iran says they are pilgrims who were visiting a shrine.