WASHINGTON (NYTIMES) - President Joe Biden said it would be "tough" to meet a May 1 deadline to withdraw all remaining US troops from Afghanistan, publicly indicating for the first time that he could extend the US troop presence there.

Mr Biden, in an interview with ABC News that aired Wednesday (March 17), said he was consulting with allies on the pace and scope of the drawdown, and added that if the deadline were to be extended, it would not be by "a lot longer."

The United States has about 1,000 more troops in Afghanistan than the 2,500 it has disclosed, The New York Times reported Sunday.

That has further complicated the current debate at the White House over whether to abide by a deal, struck last year by the Trump administration and the Taleban, that calls for removing the remaining US forces by May 1.

Mr Biden's own inclination, when he was President Barack Obama's vice-president, was toward a minimal US presence, mainly to conduct counterterrorism missions. But as president, he must weigh whether following such instincts would run too great a risk of the Taleban overwhelming government forces and taking over Afghanistan's key cities.

Many senior American commanders and intelligence analysts still argue that a full withdrawal may lead to Al-Qaeda and other groups hostile to the United States seizing wide swaths of the country.

Mr Biden, like his predecessor, has promised to end the nearly 20-year conflict and withdraw the 3,500 or so US troops in the country - down from about 12,000 troops a year ago.

The Trump deal in February 2020 caught some US allies by surprise, as the roughly 7,000 North Atlantic Treaty Organisation (Nato) troops in Afghanistan rely on the United States for logistics and security support.

If the United States does indeed try to leave by May 1, it will be almost impossible logistically to withdraw both the US and the allied forces on time, American commanders and independent analysts have said, although US officials insist it remains an option.

"That was not a very solidly negotiated deal that the president, the former president worked out," Mr Biden said in the interview with "Good Morning America" that took place Tuesday. "We're in consultation with our allies as well as the government, and that decision is in process now."

Mr Biden said it would be difficult for all service members to leave by May 1. "It could happen," he said, "but it is tough."

A spokeswoman for the White House's National Security Council, Ms Emily Horne, declined to comment further Wednesday. Other administration officials emphasised that Mr Biden had not made any final decisions.

Some of the administration's staunchest allies also voiced doubts Wednesday about meeting the May 1 deadline for a complete US withdrawal.

"It's important we get this right, and that we again keep our eyes on the strategic goal rather than work to one or another deadlines," Mr Dominic Raab, the British foreign secretary, said Wednesday in an interview with the Aspen Security Forum.

"The risk is we end up back there in 10 years' time if we don't make sure that we leave on a sustainable basis," Mr Raab said.

Even top lawmakers in Mr Biden's party are warning against withdrawing all US forces by May 1.

"To pull out within several months now is a very challenging and destabilising effort," Senator Jack Reed who leads the Armed Services Committee, said last month. Mr Reed recommended seeking an extension of the deadline.

Mr Biden is keenly aware of the risks of a total security collapse transpiring in Kabul, the Afghan capital, if all Western troops leave, and he has privately described a fall-of-Saigon scenario as haunting, aides said.

But the president also questions whether the small remaining contingent of Americans can accomplish anything after 20 years during which almost 800,000 US troops have deployed, or whether it will ever be possible to bring them home.

The administration appears to be making a major diplomatic push before confronting the stark decision on US troop levels.

Last week, Secretary of State Antony Blinken sent a blunt letter to Afghanistan's president Ashraf Ghani, earlier reported by the Afghan outlet Tolo News, that proposed several steps to revive the stalled peace negotiations between the Afghan government and the Taleban.

The letter, which asked the Afghan leader to "understand the urgency of my tone," was received by Mr Ghani as a personal slight, suggesting that he was one of the main obstacles to the process, said an Afghan official with direct knowledge of the matter.

The Taleban have threatened to resume attacks against American and other Atlantic alliance forces if the United States unilaterally decides to keep its forces beyond the May deadline.

US troops are now hunkered down in about a dozen bases and perform two main missions: counterterrorism operations and advising Afghan security forces at various headquarters.