KABUL, Afghanistan — An American airstrike in Afghanistan’s southern province of Helmand killed several members of the Afghan security forces, Afghan and American officials said Friday. The death toll was uncertain, but officials said at least nine police officers were killed.

It was the latest blow to the Afghan forces in Helmand, an area where they have been suffering heavy casualties at the hands of the Taliban.

It was the culmination of another bloody day for the Afghan police across the country. Earlier in the day, officials in northeastern Badakhshan Province said that as many as 35 police officers had been killed in a Taliban ambush.

The American strike happened late Friday afternoon in the Gereshk district of Helmand Province. The United States military has carried out as many as 52 strikes in Helmand over the past five days to support Afghan forces who have been the targets of coordinated Taliban attacks in recent days.