US authorities had long suspected that a self-described Taliban leader was an imposter, even as he engaged with Kabul over reconciliation, the top US military officer said in comments released on Friday.
Admiral Mike Mullen, chairman of the Joint Chiefs of Staff, also said he did not believe the imposter ever met with Afghan President Hamid Karzai -- contradicting media reports.
"There were very early initial suspicions. And it took a little while to verify who he was or who he wasn't. And, in fact, it turns out that he wasn't the guy that he was claiming he should be," Mullen said in an interview with CNN's Fareed Zakaria GPS due to air on Sunday.
"This was somebody that didn't have a meeting with Karzai, as far as I know. He was meeting with his intermediaries," Mullen said.
The New York Times reported this week that a man it had described as a 'Taliban leader,' who it said had taken part in secret peace talks, was in fact an impostor. It said the man met Karzai and was given "a lot of money."
The individual, identified as Taliban No 2 Mullah Akhtar Mohammad Mansour, was likely just a shopkeeper from Quetta, the Pakistani city where the Taliban leadership fled after they were toppled in late 2001, The Washington Post said.
Mullen also rejected the suggestion of an intelligence breakdown, saying "the intel world actually tipped us in the right direction with respect to that."
Some Western leaders have said the conflict in Afghanistan cannot be won militarily. Despite the presence of about 150,000 foreign troops, violence is at its worst across the country since US-backed Afghan forces ousted the Taliban in 2001.
US and NATO leaders agreed at a summit in Portugal last week to meet Karzai's timetable for foreign combat troops to leave by 2014, but pressure for talks with the Taliban has grown.
Mullen played down reconciliation efforts so far, saying: "It's been talks about talks. We really haven't made a lot of progress."
He renewed US concerns that top Afghan insurgents would not want to lay down their arms until they feel the tide has turned in the war.
The US military released a report to Congress this week acknowledging violence in Afghanistan had hit an all-time high recently as Western troops battled the expanding insurgency.
"We need to do that (push for reconciliation) from a strong position and we're just not there right now," Mullen said.
"And the Taliban don't think they're losing and the likelihood that they're going to take any significant steps with respect to reconciliation, I think, is low."
CNN released a transcript of the interview, which was recorded on Nov 24.
