Afghanistan is likely to erupt in civil war, paving the way for the resurgence of terrorist groups, America's most senior military figure warned over the weekend.
In an interview with Fox news on Sunday, General Mark Milley, chairman of the Joint Chiefs of Staff, questioned the ability of the Taliban to consolidate power in the country, dealing a blow to the Biden administration's Afghan strategy.
"I think there's at least a very good probability of a broader civil war," he said. "And that will then in turn lead to conditions that could, in fact, lead to reconstitution of al-Qaeda or a growth of ISIS or other myriad of terrorist groups."
His comments come as US Secretary of State Antony Blinken and Defence Secretary Lloyd Austin travelled to the Gulf for talks over how to contain a potential swell of terror groups.
The US is now relying on the Taliban to contain Islamist groups in Afghanistan, preventing the country becoming a terrorist sanctuary as it was in 2001 when al-Qaeda launched its attacks on September 11.
But Michael McCaul, the top Republican on the Intelligence Committee, told Fox News that America's enemies had been emboldened by a foreign policy blunder.
"We're going back to pre-9/11 right now but it's worse, it's worse because now they're fully armed with our weapons, our helicopters and pallets of our cash," he said.
Only last week Milley told journalists that it was "possible" that the US could co-operate in taking on ISIS-K, an Islamic state offshoot which was responsible for the suicide bombing at Kabul airport which killed more than 180 people including 13 American servicemen and women.
But doubts over how plausible such cooperation would be intensified over the weekend when it emerged that at least two aircraft due to carry between 600-1200 people, including 19 US citizens, had been denied permission to leave the Mazar-i-Sharif airstrip.
The planes were still grounded despite six days of talks, with the US State Department admitting it was powerless as America did not control the airspace.
Ascend, a non-governmental organisation teaching women leadership through athletics had 34 people waiting to leave.
Marina Legree, the group's executive director, told the Telegraph, that Taliban and Karn Air, which was operating the flights, were negotiating a price
"Conditions where passengers are being held are deteriorating.
"There is not enough space, gatekeepers are letting people not on the manifest come in for a bribe. I'm very concerned because I've got teenaged girls there with no protection, and the mixed, rowdy group keeps getting bigger.
The Taliban, meanwhile, has stepped up its own efforts to forge links with a sceptical West with an appeal for aid and diplomatic recognition.
Taliban spokesman Zabiullah Mujahid proffered an olive branch in interviews with German and Austrian newspapers.
"We want strong and official diplomatic relations with Germany," he told German newspaper Welt am Sonntag.
Germans were always welcome in Afghanistan and were once viewed by the Taliban as a positive influence, Mujahid told German media.
"Unfortunately, they then joined the Americans. But that is forgiven now," he said.
He also made similar comments to Austria's Kronen paper, saying: "Afghanistan urgently needs trade and diplomatic relations with these [European] countries."
Much will rest on whether the Taliban keep many of the promises they have made about not returning to their previous draconian ways.
There are already signs that things are changing for women's rights, for example.
Women attending private Afghan universities must now wear an abaya robe and niqab covering most of the face, the Taliban have ordered, and classes must be segregated by sex - or at least divided by a curtain.
In a lengthy document issued by the Taliban's education authority, they also ordered that female students should only be taught by other women, but if that was not possible then "old men" of good character could fill in.
There were also reports on Sunday of Taliban militants shooting dead an eight-month pregnant policewoman in a provincial city. The group denied any involvement and said it was investigating.