The Pentagon confirmed Thursday evening that U.S. forces were unsuccessful in their mission to rescue hostages in Afghanistan last month.

“In August, at the recommendation of [Defense Secretary Ash] Carter, President Obama authorized U.S. forces to conduct a mission in Afghanistan, aimed at recovering two civilian hostages,” Pentagon spokesman Peter Cook said in a statement. “Unfortunately, the hostages were not at the location we suspected. During the mission, U.S. forces engaged and killed a number of hostile forces. No U.S. personnel or civilians were harmed.”