President Asif Ali Zardari had a secret meeting with a group of senior Taliban operatives in April last year during which he expressed the Pakistan government's "support for their mission", a researcher studying developments in Afghanistan has alleged.
Matt Waldman, a fellow at the Carr Centre for Human Rights Policy at Harvard University, first made the claim in a controversial paper he published last year.
He recently repeated the claim to The News daily in London, saying it was corroborated by a "very senior Western official closely linked with the US-led NATO military mission" in Afghanistan.
Waldman refused to name this Western official but said he was aware of the meeting between Zardari and the Taliban operatives in a "secret prison" in Pakistan in April 2010.
He contended that the official was certain that the meeting took place and that Zardari had participated in it "possibly on the insistence of Pakistan's powerful secret services".
He said he was contacted by the official with confirmation of the meeting after he published his report "The sun in the sky: The relationship between Pakistan’s ISI and Afghan insurgents".
The Pakistan government has already dismissed Waldman's claims.
In a new report for the Royal United Services Institute, Waldman calls for negotiations with the Afghan Taliban, saying the West should accept the reality of the militants.
He says that efforts to defeat the Taliban are unlikely to succeed.
"We have to question the sustainability of a policy which requires a very large number of foreign troops with very large logistical requirement, and indeed we should consider the challenges there are in establishing effective governance in areas where the Taliban have been pushed back and certainly that has proven very difficult," he said.
The Taliban have a "difficult and complex relationship with the Pakistani state", he said.
"They are resentful of the fact that the ISI has significant influence over their movement, but they acknowledge that they need sanctuary," he said.
Waldman also said it was in the US interest to work to improve relations between India and Pakistan if it wants to see progress in Afghanistan.