President Biden will withdraw American combat troops from Afghanistan by Sept. 11, declaring an end to the nation’s longest war.

The decision, which Biden is expected to announce Wednesday, will keep thousands of U.S. forces in the country beyond the May 1 exit deadline that the Trump administration negotiated last year with the Taliban.

Officially, there are 2,500 U.S. troops in Afghanistan, although the number fluctuates and is currently about 1,000 more than that. There are also up to an additional 7,000 foreign forces in the coalition there, the majority of them NATO troops.

Mr. Biden’s decision would pull all American troops out of Afghanistan 20 years after President George W. Bush ordered an invasion after the Sept. 11 attacks on New York City and the Pentagon, with the goal to punish Osama bin Laden and his Qaeda followers, who were sheltered in Afghanistan by their Taliban hosts.

The war has cost trillions of dollars in addition to the lives of more than 2,000 U.S. service members. At least 100,000 Afghan civilians have been injured or killed.