Militants overnight fired on a NATO base in Kapisa province, just north of Kabul, said Deputy Governor Sayad Mohammad Dawood Hashimmi. When soldiers returned fire, they hit a home, killing five women, three boys and a man, he said.
A deputy Interior Ministry spokesman also said nine civilians had been killed. He asked not to be identified because the ministry hadn't yet prepared a statement.
Maj. William Mitchell, a U.S. military spokesman, said officials were looking into the incident. The NATO base in Kapisa is staffed by U.S. forces.
The news of the air strike came one day after wounded Afghans and witnesses said U.S. Marines fired on civilian cars and pedestrians after a frenzied escape from a suicide bomb and gunfire attack in eastern Afghanistan. The violence sparked by hundreds of Afghan men.
Up to 10 Afghans were killed and 34 were injured during Sunday's violence in Nangarhar province. A delegation of Afghan officials on Monday visited the site of the suicide bombing as part of investigation into the attack and its aftermath.
The back-to-back incidents of NATO or U.S. forces killing or wounding so many Afghans was likely to cause further grief in a country that has seen scores of civilians killed by international forces since the U.S.-led invasion in 2001.
Afghan President Hamid Karzai has pleaded repeatedly for Western troops to take care not to harm civilians, and in December wept during a speech lamenting civilian deaths at the hands of foreign forces.
The U.S.-based Human Rights Watch estimates that more than 100 Afghan civilians died as a result of NATO and coalition assaults in 2006. An AP tally, based on reports from Afghan, NATO and coalition officials, puts the overall civilian death toll in 2006 at 834, most from militant attacks.
Lt. Col. David Accetta, the top U.S. military spokesman in Afghanistan, said gunmen may have fired on U.S. forces at multiple points during the escape Sunday. He said it was not yet clear how the casualties happened, though he left open the possibility that U.S. forces had shot civilians.
"It's not entirely clear right now if the people killed or wounded by gunfire were killed or wounded by coalition forces gunfire or enemy attackers gunfire," he said.
Nine witnesses — including five Afghans recuperating from bullet wounds in the hospital — told The Associated Press that U.S. forces fired indiscriminately along at least a six-mile stretch of one of eastern Afghanistan's busiest highways — a route often filled not only with cars and trucks but Afghans on foot and bicycles.
"They were firing everywhere, and they even opened fire on 14 to 15 vehicles passing on the highway," said Tur Gul, 38, who was standing on the roadside by a gas station and was shot twice in his right hand. "They opened fire on everybody, the ones inside the vehicles and the ones on foot."
The tolls varied. The Interior Ministry said 10 people were killed, while the provincial health chief said eight died.
The U.S. military said eight civilians were killed and 34 wounded after earlier saying 16 were killed and 24 wounded. It did not explain the revised, lower death toll, saying only that the new figures were "the most accurate numbers to date." A U.S. Marine also was injured in the suicide blast.
At the Jalalabad hospital, several victims said the American convoy approached them on the highway and opened fire. As the convoy neared, many cars pulled over to the side of the road, but were still hit by gunfire.
"When we parked our vehicle, when they passed us, they opened fire on our vehicle," said 15-year-old Mohammad Ishaq, who was hit by two bullets, in his left arm and his right ear. "It was a convoy of three American Humvees. All three humvees were firing around."
Mohammad Karim, an 18-year-old employee at a hotel near the blast site, said he ran outside after the explosion and saw American forces fire a stream of bullets at a four-wheel drive vehicle.
"I ran to the vehicle to see how many people were inside. We found three dead bodies, and one wounded, but he was also in a very critical condition," he said. "All four people were from one family. The one who was wounded was about 20 years old."
The U.S. forces involved in the attack and ensuing gunfire were part of the U.S.-led coalition, not NATO's International Security Assistance Force. An official who asked not to be identified because he was not authorized to release the information said the troops were Marine Special Operations Forces.