US President Joe Biden has announced he will withdraw remaining US troops from Afghanistan on 11 September.
"It's time to end the forever war," Biden said in remarks from the White House's Treaty Room.
His plan is to pull out all US forces - numbering 2,500 now - one the 20th anniversary of the 2001 terror attack that was coordinated from Afghanistan.
The US cannot continue to pour resources into an intractable war and expect different results, Biden said.
After his televised remarks, Biden went to Section 60 of Arlington National Cemetery to visit the graves of US troops killed in Afghanistan.
"There's no comforting distance in history in Section 60, the grief is raw." he said. "It's a visceral reminder of the living cost of war."
The troop drawdown would begin rather than conclude by May 1, which has been the deadline for full withdrawal under a peace agreement the Trump administration reached with the Taliban last year.
The decision marks perhaps the most significant foreign policy decision for Biden so far in his presidency.
The president will then visit Section 60 of Arlington National Cemetery to honour the sacrifice of those who died in recent American conflicts.
The US administration had originally planned to withdraw troops by May 1 as part of a peace agreement the Trump administration reached with the Taliban last year.
His plan sets a firm end to two decades of war that killed more than 2,200 US troops, wounded 20,000, and cost as much as €835bn ($1 trillion).
The conflict largely crippled al-Qaeda and led to the death of Osama bin Laden, the architect of the September 11 attacks.
It recently became clear that an orderly withdrawal of the remaining troops would be difficult and was unlikely by May 1.
No military solution
Defence officials and commanders had argued against the May 1 deadline, saying the US troop withdrawal should be based on security conditions in Afghanistan, including Taliban attacks and violence.
Officials have quietly acknowledged that there are hundreds more in Afghanistan than the official 2,500 number.
The president's decision risks retaliation by the Taliban on US and Afghan forces, possibly escalating the 20-yea conflict.
It will also reignite political division over America's involvement in what many have called the endless war.
The German Defence Minister also said NATO soldiers engaged in Afghanistan are likely to withdraw by September.
Speaking ahead of a meeting of defence and foreign ministers of NATO members on Wednesday, Annegret Kramp-Karrenbauer said: "I am for an orderly withdrawal, which is why I suppose we will decide this today.”
During a videoconference the Alliance is expected to make a decision on whether the time is right to end the “Resolute Support” mission in Afghanistan which includes 9,600 troops from 36 countries.
An intelligence community report issued on Tuesday about global challenges for the next year said prospects for a peace deal in Afghanistan are "low" and warned that "the Taliban is likely to make gains on the battlefield.
If the coalition withdraws support the Afghan government will struggle to control the Taliban, the report says.
Reaction to the new deadline has been mixed.
"Precipitously withdrawing US forces from Afghanistan is a grave mistake," said Senate Republican leader Mitch McConnell, R-Ky. "It is retreat in the face of an enemy that has not yet been vanquished and abdication of American leadership."
'Sacrificed too much'
Sen. Jim Inhofe of Oklahoma, the ranking Republican on the Senate Armed Services Committee, slammed the move as a "reckless and dangerous decision."
He said any withdrawal should be conditions-based, adding that arbitrary deadlines could put troops in danger, create a breeding ground for terrorists and lead to civil war in Afghanistan.
Democrat, Sen. Jack Reed, D-R.I., chairman of the Armed Services Committee, said President Donald Trump's May 1 deadline limited Biden's options.
"We still have vital interests in protecting against terrorist attacks that could be emanating from that part of the world, but there are other areas, too, we have to be conscious of," Reed said.
But at least one senior Democrat expressed disappointment; Sen. Jeanne Shaheen of New Hampshire said in a tweet that the US "has sacrificed too much to bring stability to Afghanistan to leave without verifiable assurances of a secure future."
Taliban spokesman Zabihullah Mujahed told the AP that the religious militia is waiting for a formal announcement to issue its reaction. The Taliban previously warned the US of "consequences" if it reneged on the May 1 deadline.
In a February 2020 agreement with the Trump administration, the Taliban agreed to halt attacks and hold peace talks with the Afghan government, in exchange for a U.S. commitment to a complete withdrawal by May 2021.
When Biden entered the White House in January, he began a review of the February 2020 agreement and has been consulting at length with his defence advisers and allies.
In recent weeks, it became increasingly clear that he was leaning toward defying the deadline.
"It's going to be hard to meet the May 1 deadline," Biden said in March. "Just in terms of tactical reasons, it's hard to get those troops out." He added, "And if we leave, we're going to do so in a safe and orderly way."