Washington, D.C.: All US troops would withdraw from Afghanistan over the next three to five years under a new Pentagon plan being offered in peace negotiations that could lead to a government in Kabul that shares power with the Taliban.

The rest of the international force in Afghanistan would leave at the same time, after having mixed success in stabilising the country since 2001. The plan is being discussed with European allies and was devised, in part, to appeal to President Donald Trump, who has long expressed scepticism of enduring American roles in wars overseas.

The plan calls for cutting by half, in coming months, the 14,000 US troops currently in Afghanistan. It would give the 8,600 European and other international troops the task of training the Afghan military — a focus of the Nato mission for more than a decade — and largely shift American operations to counterterrorism strikes.

Various elements of the plan were shared with The New York Times by more than a half dozen current and former American and European officials. It intends to help talks with the Taliban that are being led by Zalmay Khalilzad, the US special envoy.

So far, the plan has been met with broad acceptance in Washington and Nato headquarters in Brussels. But US officials warned that Trump could upend the new plan at any time.

And officials said that even if the peace talks broke down, the United States would go forward with shifting to counterterrorism missions from training Afghan forces.

Until the final withdrawal, several thousand American forces would continue strikes against Al Qaida and Daesh, including on partnered raids with Afghan commandos. The counterterrorism missions, and the military’s dwindling presence, are also critical to allowing the CIA to operate in Afghanistan.

Lt. Col. Kone Faulkner, a Pentagon spokesman, said no decisions had been made as peace talks continued. The Defence Department “is considering all options of force numbers and disposition,” Faulkner said.

But European allies said they had been consulted about the proposal — a stark contrast to Trump’s surprise announcement in December to withdraw American forces from Syria.

“The Europeans are perfectly capable of conducting the training mission,” James Stavridis, a retired US admiral and former top Nato commander who is now with the Carlyle Group private equity firm. “It is a smart division of labour to have the United States shift the bulk of its effort toward the special forces mission and having the Europeans do the training mission.”

Stavridis said the two missions would be coordinated, including American logistical support and military backup for the European troops.

On Monday, US diplomats met with the Taliban in Qatar in the highest-level negotiations yet, including the attendance of Gen. Austin S. Miller, the commander of the international mission in Afghanistan. The negotiations paused on Wednesday and are set to resume on Saturday.

The two sides have sought to flesh out a framework agreement, decided in principle last month, for the full withdrawal of foreign troops and assurances by the Taliban to prevent terrorist groups that seek to attack the United States from using Afghan territory as a safe haven.

The Afghan government has not been a part of the negotiations because of Taliban reluctance to talk to President Ashraf Ghani or his envoys.

Taliban negotiators deeply oppose the proposal for US counterterrorism troops to remain in Afghanistan for up to five years, and officials were unsure if a shorter period of time would be accepted by the militants’ rank and file.

Scaling back the training mission could leave the beleaguered Afghan military not just vulnerable to attacks, but at risk of fracturing. In January, Ghani announced that more than 45,000 Afghan troops had died since 2014; Pentagon officials have called their casualty numbers unsustainable.

Despite pouring billions of dollars into the Afghan military for more than a decade, Pentagon audits show that a renewed effort to modernise the fledgling Afghan air force will most likely not be self-sufficient until the mid-2030s.

Speaking to lawmakers in December, the incoming commander for US troops in the Middle East, Lt. Gen. Kenneth F. McKenzie Jr., said that Afghan forces could not sustain themselves without American and Nato support.

“I do know that today it would be very difficult for them to survive without our and our coalition partners’ assistance,” he said.

Current and former Defence Department officials said limiting US assistance to the Afghan military would require a delicate balance of providing just enough material support for the Nato training mission, known as Resolute Support, to ensure that Western allies remain invested without sacrificing counterterrorism operations.

European allies cited Miller as describing the reduced troop levels as about “doing more with less.”

One former Defence Department official with knowledge of the talks said more American support for the training mission could be based outside Afghanistan and flown in when needed. European countries have relied heavily on US bases, supplies and other logistics throughout the war.

Laurel Miller, who was a top State Department official working on Afghanistan and Pakistan policy during the Obama and Trump administrations, said it was risky to change the military mission in Afghanistan without a peace plan in place.

“The idea of scaling down to a small CT-only mission has long been discussed in the US government,” she said. But, she said, “if you stop backing up Afghan forces in their main fight, you can’t very well keep working on your narrower priorities in isolation with Afghanistan falling apart around you.”

It is also possible that international funding support for the Afghan government could end up going to the Taliban under a power-sharing agreement. But American and European officials called it critically necessary to continue funding Afghan security forces.