KABUL, Afghanistan — An American airstrike accidentally killed at least eight Afghan police officers in southern Afghanistan on Thursday, American and Afghan officials said.

The police had requested air support after a Taliban attack near their outpost near the outskirts of Lashkar Gah, the capital of Helmand Province.

Attaullah Afghan, the head of Helmand’s provincial council, estimated the police death toll at 17, including a commander and his assistant, and said that 14 more people were wounded.

Col. Dave Butler, a spokesman for the American-led mission in Afghanistan, said that the Americans had coordinated with Afghan officials and had confirmed that the “areas were clear of friendly forces.”