JALALABAD, Afghanistan (Reuters) - A suspected U.S. drone strike against Islamic State in Afghanistan killed at least 21 people on Wednesday, most of them militants but possibly including some civilians, Afghan officials said.

Civilians casualties in U.S. air strikes have long been a source of friction between the Afghan government and Western allies fighting the Taliban-led insurgency since 2001.

The strike in Nangarhar province, on the eastern border with Pakistan, killed 21 people, at least three of them civilians, and wounded another 11, according to Malem Mashooq, the governor of Achin district where the attack occurred.

One of the wounded told Reuters that the attack struck a house where people were sleeping after a gathering to welcome a local elder who had recently returned from the Hajj pilgrimage.

“I saw dead and wounded bodies everywhere,” Raghon Shinwari said, lying on a hospital bed in Jalalabad city.

Mohammed Ali, the Achin district police chief corroborated that account.

“They were in a house to visit someone who had just come from the Hajj pilgrimage,” he said. “A drone targeted the house and killed most of them.”

Provincial police spokesman Hazrat Hussain Mashriqiwal said several Islamic State leaders had been killed, but he denied there were any noncombatants among the victims.

A spokesman for the U.S. military command in Kabul confirmed that U.S. forces conducted a “counter-terrorism” air strike in Achin, but would not discuss the details of the target.

“U.S. Forces - Afghanistan takes all allegations of civilian casualties very seriously,” said Brigadier General Charles Cleveland.

“We are aware of some claims of Afghan casualties, and are currently reviewing all materials related to this strike. We are continuing to look into these allegations.”

Determining which victims were civilians and which were militants would not be possible until an investigation was complete, said Attaullah Khogyani, a spokesman for the provincial governor.

Islamic State has attracted hundreds, perhaps thousands, of fighters in Afghanistan and Pakistan to join its ranks, and it holds some territory in Nangarhar, and Achin was a stronghold for the group.

But it has not been able to expand its influence in Afghanistan beyond a few districts and the Taliban remain the dominant militant force.

Thousands of U.S. troops remain in Afghanistan, with many recent air strikes and special operations missions aimed at Islamic State in Nangarhar, but they have also been helping Afghan forces fight Taliban elsewhere in the country.

Between January and August this year, American aircraft released more than 800 weapons and flew more than 3,500 close air support missions in Afghanistan, according to U.S. military reports.</s>A US drone strike has killed at least 21 people in the eastern Nangarhar province, with Afghan sources saying that more than a dozen of them were civilians.

Esmatullah Shinwari, a Nangarhar lawmaker, told the Associated Press that a crowd had gathered at the tribal leader’s house in the Achin district to welcome home his return from the annual Hajj pilgrimage to Saudi Arabia when the drone struck.

At least 12 people were wounded in the attack, including the tribal leader, he said.

Unnamed Afghan sources have said at least 13 of the victims were civilians.

The spokesman for the US military in Afghanistan, Brigadier General Charles Cleveland, confirmed that a “counter-terrorism airstrike” had been conducted in Achin district early Wednesday.

“US forces did conduct one counter-terrorism airstrike in Achin district, Nangarhar Province, Sept. 28, and for operational security reasons, we do not discuss the details of counter-terror operations,” he said in a statement.

“We are aware of some claims of Afghan casualties,” he said, adding that investigations were underway.

Local Afghan sources said the US drone attack left at least 25 civilian casualties.

The people of Afghanistan have been suffering from violence and insecurity since the US and its allies invaded the country as part of Washington’s so-called war on terror in 2001. Many parts of the country still remain plagued by militancy despite the presence of foreign troops. The military invasion removed Taliban, but militants still push to wrest control over the war-ravaged country.</s>A suspected US drone strike against Islamic State in Afghanistan has killed 18 people, Afghan officials have said. 



The strike in Nangarhar province on the eastern border with Pakistan killed 15 militants and three civilians, said Mohammed Ali, the police chief of Achin district, where the attack occurred. 



“They were in a house to visit someone who had just come from the Hajj pilgrimage,” he said. “A drone targeted the house and killed most of them.” 



The provincial police spokesman Hazrat Hussain Mashriqiwal said several Isis leaders had been killed, but he denied there were any noncombatants among the victims. 



Civilian casualties in US airstrikes against Taliban and other militants in Afghanistan have long been a source of friction between the allies who have been fighting since 2001 to end militant opposition to the government in Kabul.

Isis has enticed hundreds, perhaps thousands, of fighters in Afghanistan and Pakistan to join, and it holds some territory in Nangarhar, with Achin a stronghold. But it has not been able to expand its influence in Afghanistan beyond a few districts and the Taliban remain the dominant Islamist force. 



A spokesman for the US military command in Kabul confirmed that American forces conducted a counter-terrorism airstrike in Achin, but would not discuss the details of the target. 



“US forces Afghanistan takes all allegations of civilian casualties very seriously,” said Brig Gen Charles Cleveland. “We are aware of some claims of Afghan casualties, and are currently reviewing all materials related to this strike. We are continuing to look into these allegations.”

Determining which victims were civilians and which were militants would not be possible until an investigation was complete, said Attaullah Khogyani, a spokesman for the provincial governor. 



Thousands of US troops remain in Afghanistan, with many recent airstrikes and special operations missions aimed at Isis in Nangarhar, as well as helping Afghan forces in their fight against the Taliban in various parts of the country. 



Between January and August, American aircraft released more than 800 weapons and flew more than 3,500 close air support missions in Afghanistan, according to US military reports.</s>An unauthorised drone led to a complete 27 minute shutdown at @DubaiAirports https://t.co/Wv6KCKJhs8</s>The airstrike occurred in the early morning on Wednesday, hitting what U.S. officials said was an Islamic State target in Achin district of Nangarhar province.

The U.N. Assistance Mission in Afghanistan (UNAMA) said some militants may have been killed in the strike, but many of the victims were civilians, including students, a teacher, and members of families considered to be "pro-government".

"UNAMA reiterates the need for all parties to the conflict to adhere to their obligations under international humanitarian law," the United Nations said in a statement.

"UNAMA calls on the government and international military forces to launch a prompt, independent, impartial, transparent, and effective investigation into this incident."

The civilians had gathered in a village to welcome the return of a local elder who had completed the Hajj pilgrimage to Mecca and were sleeping when the strike occurred, according to witnesses.

The U.S. military command confirmed it conducted an air strike in Achin aimed at Islamic State militants, but said it is gathering information on the allegations of civilian casualties.

"We take every possible measure to avoid civilian casualties in these operations, and will continue to work with Afghan authorities to determine if there is cause for additional investigation," U.S. forces said in a statement.</s>Civilians were among at least 18 people killed in a US air strike against Islamic State militants in eastern Afghanistan on Wednesday, officials said, with conflicting claims about the number of civilian deaths.

The attack happened in Achin district, a hotbed of IS insurgents in Nangarhar province near the border with Pakistan, as local residents gathered to welcome a tribal elder who had recently returned from the hajj pilgrimage.

“Three civilians lost their lives in this strike,” Achin police chief Mohammad Ali told AFP, adding that 15 militants were also killed.

But Esmatullah Shinwari, a Nangarhar MP, said the strike killed 13 civilian relatives of the local elder. Six IS fighters were also killed, he added.

The American military said it conducted a “counter-terrorism airstrike in Achin” on Wednesday, adding it was aware of claims of civilian casualties.

“We… are currently reviewing all materials related to this strike,” US military spokesman Charles Cleveland said in a statement.

“US Forces-Afghanistan takes all allegations of civilian casualties very seriously.”

There was no information on whether it was an attack by a drone or a piloted aircraft.

Islamic State first emerged in Afghanistan in late 2014 and has since violently challenged the much larger Afghan Taliban movement in parts of the country’s east.

But the fighters have steadily lost territory in recent months because of stepped-up US airstrikes and a ground campaign by Afghan forces in Nangarhar.

They are confined to two or three districts including Achin, according to Afghan and US officials.

Civilian and military casualties caused by NATO forces have been one of the most contentious issues in the 15-year campaign against the insurgents, prompting harsh public and government criticism.

A US air strike killed eight Afghan policemen earlier this month in the southern province of Uruzgan in the first apparent “friendly fire” incident since American forces were given greater powers to strike at insurgents in June.

The new authority gave the US-led NATO troops greater latitude to order air strikes in support of Afghan troops.
A U.S. drone strike in Nangarhar Province kills at least 21 people.