Biden to Withdraw All Combat Troops From Afghanistan by Sept. 11

But Mr. Biden’s decision drew fire from Republicans.

“This is a reckless and dangerous decision,” said Senator James M. Inhofe of Oklahoma, the ranking Republican on the Senate Armed Services Committee. “Arbitrary deadlines would likely put our troops in danger, jeopardize all the progress we’ve made, and lead to civil war in Afghanistan — and create a breeding ground for international terrorists.”

President Donald J. Trump had set a withdrawal deadline for May 1, but he was known for announcing, and reversing, a number of significant foreign policy decisions, and Pentagon officials continued to press for a delay. Mr. Biden, who has long been skeptical of the Afghan deployment, spent his first three months in office assessing that timeline.

The Afghan central government is unable to halt Taliban advances, and American officials offer a grim assessment of prospects for peace in the country. Still, American intelligence agencies say they do not believe Al Qaeda or other terrorist groups pose an immediate threat to strike the United States from Afghanistan. That assessment has been critical to the Biden administration as it decided to withdraw most of the remaining forces from the country.

A senior administration official said the troop withdrawal would begin before May 1 and conclude before the symbolic date of Sept. 11. Any attacks on withdrawing NATO troops, the official said, would be met with a forceful response.

Taliban leaders have long pledged that any breach of the deadline means that their forces will again begin attacking American and coalition troops. Under a withdrawal deal negotiated during the Trump administration, the Taliban mostly stopped those attacks — but in past weeks, they have rocketed American bases in Afghanistan’s south and east.

In public statements on Tuesday, Taliban leaders focused not on Mr. Biden’s decision for a full withdrawal — leaving behind a weak central government that has proved incapable of halting insurgent advances around the country — but rather on the fact that the administration was going to miss the May 1 deadline.

“We are not agreeing with delay after May 1,” Zabihullah Mujahid, a Taliban spokesman, said on local television. “Any delay after May 1 is not acceptable for us.”