A man who has been representing Taliban senior leaderhip in secret talks with the Afghan government appears to have been an impostor.
The man, calling himself Mullah Akhtar Muhammad Mansour, the Taliban's second-ranking official, was exposed after another man who knows Mansour did not recognise him during a negotiation session, the New York Times reported on Monday.
The secret talks with the impostor had been going on for months and were used by senior US officials to claim progress on the diplomatic front in the Afghan war.
Nato and Afghan officials told the New York Times they held three meetings with the man, who allegedly received large sums of money to take part in the negotiations.
The fake Taliban leader, who travelled from across the border in Pakistan, even met with Hamid Karzai, the Afghan president, in the presidential palace in Kabul, the capital. He was flown to the capital on Nato aircraft.
Karzai denied meeting Mansour "or a man claiming to be him" and dismissed the report as international media propaganda. "Don't trust the New York Times," he said.
Suspicion
Al Jazeera's Sue Turton, reporting from Kabul, said US officials always held suspicion about the identity of the man.
"Americans here admit that they don't often know what these people look like; that they can only go on who they say they are because these people have been hiding and fighting this insurgency for so long," she said.
"So they have to go on trust to a certain extent, and it seems that this particular man has managed to get away with it.
"There are so many channels of different meetings going on. Whether they are held behind the scenes, whether they are presidential meetings or whether they are just members of the High Council for Peace. It is very difficult to know who they are talking to."
Nato said it also helped to facilitate the discussions by providing air transport and securing roadways for two other Taliban leaders coming from Pakistan. The status of these Taliban leaders said to be involved is not clear.
While the Afghan government still harbours hopes that the man would return for another round of negotiations, US officials said they had concluded that the man in question was not Mansour. How the US reached this definitive conclusion is unclear.
Mullah Omar, the one-eyed Taliban leader, last week dismissed reports of Taliban involvement in peace talks to bring an end to the nine-year conflict as "misleading rumours."
Last October Karzai confirmed that unofficial talks between his government and the Taliban aimed at ending the nine-year conflict had been going on for "quite some time".
Burhanuddin Rabbani, the former Afghan president, chairs the peace council tasked with brokering an end to the war with the Taliban.