WASHINGTON — A U.S. official said three Drug Enforcement Administration agents were killed today when a U.S. military helicopter went down in western Afghanistan.

The casualties mark the first DEA deaths in Afghanistan since the drug agency began operations there in 2005. The official spoke on condition of anonymity because no formal announcement has been made. Seven U.S. service members were also killed in the crash in the west of the country. Officials said the helicopter had left the scene of a fire fight with insurgents.

U.S. authorities did not immediately give a cause for the crash. A Taliban spokesman claimed they shot down a helicopter in the northwest Badghis province but it was impossible to verify the claim.

By The Associated Press