Two security experts told This Week in Asia the Taliban might have provided intelligence to the US for its recent retaliatory drone strikes against Isis-K militants near the city of Jalalabad and in Kabul. The terror group operates in Afghanistan and Pakistan.

The August 26 suicide bombing and assault on Kabul airport killed some 170 civilian evacuees and 13 US soldiers, with the Taliban saying at least 28 of its fighters manning the security perimeter at the airport also died in the attack.

Faran Jeffery, deputy director and head of the South Asia desk on terrorism at the Britain-based Islamic Theology of Counter Terrorism (ITCT) think tank, pointed out that Jalalabad was effectively under Taliban control, so it was "entirely plausible the Taliban could have helped in some way with pinpointing the target [through its] vast network of spies and informants".

Michael Kugelman, senior South Asia associate at the Washington-based Wilson Center, drew a similar conclusion, saying one could not "rule out the Taliban having provided intelligence to the US about the location of Isis-K members targeted in US air strikes in recent days".

"The US has looked to the Taliban as a least-bad option for potential counterterrorism cooperation, but that has largely been aspirational more than real. Recent signalling from Washington, however, suggests that it may be amenable to pursuing real cooperation," he added.

"Talk of an alliance comes two decades since then president George W. Bush declared following the September 11 attacks that the Taliban was a sworn enemy for "aiding and abetting murder".

Washington had already relied on the Taliban for some elements of security protection at the Kabul airport in the run-up to the final withdrawal of its troops on Tuesday, and prior to that had provided limited intelligence to the group in their crackdown on terrorism.

"The idea of the US partnering with the organisation that killed its soldiers for nearly two decades is certainly quite unpalatable. But then again, interests typically trump morality in international relations," said Kugelman. "The US will partner with the Taliban if it thinks that can best advance its interests in degrading the Isis-K threat."