WASHINGTON — The No. 2 American commander in Afghanistan says he believes the stage has been set for winning the war.

Army Lt. Gen. Mark Milley told reporters on Wednesday that while more fighting is ahead, and the outcome is not assured, he believes the Taliban no longer are capable of overthrowing the U.S.-backed Afghan government.

Milley said the war's momentum has shifted in favor of the Afghan government, even though its army and police are taking heavy casualties — 50 to 100 killed per week. He said it is an "open question" whether the Afghans can sustain that loss rate, but he also predicted that the casualties would not "break" the Afghans' will.

The U.S. and its NATO allies are to complete their combat mission in Afghanistan in December 2014.