• President Joe Biden will withdraw all U.S. troops from Afghanistan by September, missing a crucial May 1 deadline that was brokered by the Trump administration.
• Biden's removal of U.S. forces will coincide with the 20th anniversary of the Sept. 11, 2001, terror attacks that triggered the nation's entry into what would become its longest war.

WASHINGTON — President Joe Biden will withdraw all U.S. troops from Afghanistan by September, missing a crucial May 1 deadline that was brokered by the Trump administration, a senior administration official said on Tuesday.

Biden's removal of U.S. forces will coincide with the 20th anniversary of the Sept. 11, 2001, terror attacks that triggered the nation's entry into what would become its longest war. The official, who spoke on the condition of anonymity, said the withdrawal of U.S. and foreign troops from the war-torn country could happen well before September.

"We will reposition our counterterrorism capabilities retaining significant assets in the region to counter the potential reemergence of a terrorist threat to the homeland from Afghanistan and to hold the Taliban to its commitment to ensure Al Qaeda does not once again threaten the United States or our interests or our allies," the official said.

The administration understands that "military force would not solve Afghanistan's internal political challenges," the official said.

Biden is slated to announce his plan on Wednesday.

In February 2020, the Trump administration brokered a deal with the Taliban that would usher in a permanent cease-fire and reduce further the U.S. military's footprint from approximately 13,000 troops to 8,600 by mid-July last year.

By May 2021, all foreign forces would leave Afghanistan, according to the deal. The majority of troops in the country are from Europe and partner nations. About 2,500 U.S. service members are now in Afghanistan.

Last month, Biden told reporters during his first press conference that he could not yet commit to the May 1 deadline.

"It's going to be hard to meet the May 1 deadline," Biden said, adding, "it is not my intention to stay there for a long time."

When asked if U.S. service members would remain in Afghanistan another year, Biden said he did not see that being the case.

"We are not staying a long time. We will leave, the question is when we leave," the president said, adding that his administration was in consultations with NATO allies and partners in the region.

The announcement comes as Secretary of State Antony Blinken and Secretary of Defense Lloyd Austin meet with NATO partners in Brussels. NATO joined the international security effort in Afghanistan in 2003 and currently has more than 7,000 troops in the country.

The wars in Afghanistan, Iraq and Syria have cost U.S. taxpayers more than $1.57 trillion collectively since Sept. 11, 2001, according to a Defense Department report. 

Read more: Biden should keep U.S. troops in Afghanistan past May deadline, study group says