“Three families were living in the house which was bombed; 11 people, including eight women, were killed,” Hawas Khan Kochai, a resident of the Dasht e Bari area, said by phone. “We recovered all the bodies with an excavator after several hours, but two children are still missing.”

Capt. Bill Salvin, a spokesman for the United States military in Afghanistan, said an American helicopter had made a “precautionary landing because of a maintenance issue” in Logar on Wednesday, but there were no casualties. He would not say whether the airstrikes occurred in the area where the helicopter had landed.

“We are looking into reports of civilian casualties,” Captain Salvin said.

United States military officials said recently that they had increased American air support and personnel to help train Afghan security forces since President Trump announced more than a week ago his new strategy for the war in Afghanistan. The air support is meant to bolster Afghan forces who are fighting difficult battles against a resurgent Taliban, who have regained control of portions of the country.

From January through July, the United States military dropped 1,245 bombs and other ordnance in Afghanistan, over 500 more than had been dropped during the same period last year. The Afghan Air Force, too, has been increasingly active, but its bombs are harder to track.

On Monday, residents and officials in Herat Province in western Afghanistan said airstrikes there had killed more than a dozen civilians. A spokesman for the Afghan Ministry of Defense said that the strikes had been carried out by the Afghan Air Force and that 18 Taliban fighters had been killed.