KABUL, Afghanistan -- Afghan officials said fighter aircraft battling militants accidentally killed up to 27 Afghans walking to a wedding ceremony in eastern Afghanistan early Sunday, the second military attack in three days with reports of civilian deaths.
The U.S. military blamed the claims on militant propaganda and said its missiles only struck insurgents.
President Hamid Karzai had already ordered an investigation into allegations that missiles from U.S. helicopters struck civilians Friday in eastern Afghanistan, though the Defense Ministry said Sunday that attack on the Nuristan-Kunar border killed or wounded 20 militants.
U.S. Army Gen. David D. McKiernan, the commander of NATO forces in Afghanistan, said the two incidents were being investigated. He noted that militants hide among and intimidate civilians.
U.S. spokesman 1st Lt. Nathan Perry said the military has repeatedly seen militants falsely claim civilian were killed.
"Whenever we do an airstrike the first thing they're going to cry is 'Airstrike killed civilians' when the missile actually struck militant extremists we were targeting in the first place," Perry said. "At this time we don't believe we've harmed anyone except for the combatants."
In the second incident early Sunday, the chief government official in the Deh Bala district of Nangarhar province said villagers reported that as many as 27 people walking in a group toward a wedding were killed in a bombing. Up to 11 other people were wounded, Haji Amishah Gul said.
Nuristan provincial police chief spokesman Ghafor Khan said that fighter aircraft attacked a group of militants near the village of Kacu, but that one of the missiles went off course and hit the wedding party. Khan said many militants were killed in the attack as well.
Both officials relied on reports called in by telephone from villagers.
The area was too remote for officials or reporters to reach.
Gul said the group killed included men, women and children. Six of those wounded were taken to the provincial hospital in Jalalabad. Lal Wazir, an Afghan who helped bring the wounded to the hospital, said the airstrike occurred at 6:30 a.m.
"The wedding participants were on their way to the groom's house," Wazir said outside the hospital, his tunic covered in blood after carrying some of those wounded.
"They stopped in a narrow location for rest. The plane came and bombed the area. There were between 80 to 90 people altogether. We have carried six of the injured to this hospital, and more might be coming. The exact number of casualties is not clear," he said.
A U.S.-led coalition statement said an airstrike killed several militants in Nangarhar.
The issue of civilian casualties has caused friction between the Afghan government and U.S. and NATO troops, and has weakened the standing of Western-backed Karzai in the eyes of the population.
Karzai has repeatedly called for better coordination between Afghan and foreign troops in pursuing militants through populated areas, and for international troops to cut down on civilian casualties. Deaths of ordinary Afghans caused a huge outcry last year, but there have been fewer accusations of such killings in recent months.
McKiernan said NATO uses a "very judicious and strict application of lethal force."
"Civilian casualties are very, very important in this campaign. One is one to many," he said. "I do think we have ... the right procedures in place to mitigate and minimize any collateral damage to people or material."
Perry said Sunday that military reports still indicated that the Friday airstrike by coalition helicopters in Nuristan hit two vehicles carrying militants who had attacked a NATO base with mortars.
Karzai suggested that Afghan civilians may have been fleeing at the time of the strike because of a warning from the U.S. coalition.
"Coalition forces are saying that this operation was against armed insurgents in the area, but Gov. Nuristani is insisting that three hours before this airstrike, people were informed by international forces that they should leave the area because of a possible airstrike against insurgents," Karzai said in a statement.
Elsewhere, in the southern province of Helmand -- the country's other hotly contested region -- a clash killed seven Taliban and two police, provincial police chief Mohammad Hussein Andiwal said. Five other officers were wounded during the Saturday fight in Nawa district, he said.
The coalition said several militants were also killed Friday during an operation in Ghazni province.
More than 2,100 people -- mostly militants -- have been killed in insurgency-related violence in Afghanistan this year. More than 8,000 people died in attacks last year, according to the U.N., the most since the 2001 U.S.-led invasion.
The number of militant attacks has been on the rise this summer compared with the same period last year, NATO officials say.