American diplomats are so worried that Donald Trump will unilaterally pull all U.S. troops out of Afghanistan that they have opened direct talks with the Taliban in a bid to reach a peace deal that might hold in Americans' absence.

The Pentagon has 15,000 troops there trying to win a 17-year war started by President George Bush in a bid to destroy al-Qaeda's strongholds.

Trump approved thousands of those fighters just 11 months ago, but diplomats are worried he will run out of patience.

'Just because he signed on to this policy in August, most of the people who work for him have no trust and confidence that he’ll stick to his policies,' a former senior U.S. official told NBC News.

The Taliban has already held their first direct contact with U.S. official in a preliminary discussion about future peace talks, a senior member of the insurgent group claimed on Saturday.

That would mark one of the most significant developments amid efforts to find a negotiated end to the country's protracted war.

The Taliban source described as 'useful' a meeting with Alice Wells, America's top diplomat for South Asia, last week.

The Taliban claim to have held discussions with the U.S which, if correct, marks one of the most significant developments amid efforts to find a negotiated end to the country's protracted war. Pictured: Taliban fighters west of Kab.ul on September 26, 2008

In this photo taken on June 17, 2018, Afghan Taliban militants and residents stand on a armoured Humvee vehicle of the Afghan National Army as they celebrate a ceasefire on the third day of Eid in Maiwand district of Kandahar province

The militant said the meeting was held in the small Middle Eastern country of Qatar, where the Taliban have maintained a political office since 2013.

'The environment was positive and the discussion was useful,' the Taliban official said on condition of anonymity because he was not authorized to speak to the media.

U.S. officials neither confirmed nor denied a meeting took place. However, Wells was in Doha, the Qatar capital, this week.

In a statement following her return, the State Department said only that Wells had been in Doha, had met with the ruling family and 'the United States is exploring all avenues to advance a peace process in close consultation with the Afghan government.'

Any talks about a future political setup would be between the Taliban and the Afghan government, the statement said.

U.S. Army from NATO and Afghan commando forces are pictures in a checkpoint during a patrol against ISIS militants at the Deh Bala district in the eastern province of Nangarhar Province

The Taliban have long demanded direct talks with Washington, saying they do not want to talk politics with the U.S. but instead meet face to face to discuss Washington's concerns - particularly its security concerns - about the Taliban and Taliban involvement in Afghanistan's future.

They also say they want a time frame for the withdrawal of the roughly 15,000 U.S. and NATO troops still in Afghanistan.

It was not clear when the next meeting would be held or with whom, but the Taliban official who spoke out was certain one would be held.

A former Taliban minister and ex-head of their political committee, Aga Jan Mohtism, who has maintained close contacts with the insurgent group, also confirmed a meeting in Doha took place earlier this week.

'The Taliban want to solve their problems with the Americans to end the invasion,' he said.

The Taliban have argued that the Afghan government cannot act independent of Washington. They also say that unless they can allay U.S. concerns about the group, an agreement with Kabul would be meaningless.

The Taliban source described as 'useful' a meeting with Alice Wells, America's top diplomat for South Asia, last week

During the Taliban's five-year rule that ended with the 2001 US-led invasion, leader Mullah Mohammed Omar said regardless of whatever concessions they agreed to, including allowing girls to attend school, it would not gain them international recognition as long as the U.S. refused to accept them.

The current leadership, most of whom are Mullah Omar's contemporaries, still believe their future in Afghanistan can be guaranteed only if the United States' concerns are addressed.

Until now, Afghan President Ashraf Ghani's national security team has said it is ready to hold talks with the Taliban at any time and that their allies, including the US, should participate only as observers.

In Kabul on Saturday, Shah Hussain Murtazawi, deputy spokesman for Ghani, repeated the government's oft-stated position that peace talks should be 'Afghan owned and Afghan led, any assistance the allies provide [would be in] a supportive role.'

Murtazawi did not comment directly on the meeting in Doha or say whether Ghani's government was aware that the meeting had been held.

A previous attempt at direct talks between Washington and the Taliban in 2013 also in Doha, was scuttled when then-Afghan President Hamid Karzai objected to the Taliban calling its office the Islamic Emirate of Afghanistan - the name of its government - and flying the flag the movement flew when they ruled Afghanistan.

The current Taliban leadership, most of whom are Mullah Omar's contemporaries, still believe their future in Afghanistan can be guaranteed only if the United States' concerns are addressed. Pictured: A file photo of Taliban fighters

Afghan security forces stands next to Taliban militants as they are to the media in Ghazni province on April 14, 2018

At the time the direct talks, which the Taliban also said would be restricted to U.S. concerns about the movement and troop withdrawal, was to be followed by talks between the Taliban and the Afghan government.

There was also a suggestion at the time that the talks would include the freedom of five Taliban held in the U.S. prison at Guantanamo Bay and the release of captured U.S. soldier Bowe Bergdahl.

His release was eventually secured in May 2014 in exchange for the five Taliban prisoners, who are living in Doha.

The U.S. still has around 14,000 troops in Afghanistan after President Trump decided to increase the U.S. military's presence there by several thousand last year.

Some 3,550 international coalition troops, including 2,413 Americans, have died in Afghanistan since the invasion in 2001.