The top commander in Afghanistan suggested Tuesday that the United States suspected all along that a man leading peace talks on behalf of the Taliban was an impostor, even though the bogus militant was allegedly receiving payments from the West while he was duping them. 

Gen. David Petraeus, speaking in Berlin, seemed to confirm newspaper reports that said the man claiming to be senior Taliban commander Mullah Akhtar Mohammad Mansour during negotiations was an impersonator. The general described the Taliban outreach over the past six-to-eight months as "preliminary," saying some of the senior Taliban leaders "have been recognized as being legitimate" -- but not all. 

"There has been skepticism about one of these all along and it might well be that that skepticism was well founded," Petraeus said. 

The acknowledgement came after other U.S. officials refused to comment on the claim -- first reported in The New York Times and Washington Post -- that Western officials were dealing in high-level discussions with a fake. 

White House spokesman Bill Burton earlier referred all questions to the Afghan government. State Department spokesman Mark Toner said he did not have "a lot of information" about the issue, but noted that the reports underscore the reality that "intelligence is a difficult ... thing" in these circumstances. 

The Times reported that the man claiming to be Mansour was flown to Kabul on a NATO aircraft to meet with Afghan President Hamid Karzai. According to the report, he was given money to participate in the talks, though Burton said "U.S. money" did not go to him. 

Karzai vigorously disputed the reports, saying he never met with anybody by that name and calling the claims "propaganda" during a press conference in Kabul. 

"Don't listen to the international media regarding news about the Taliban. Don't listen to them. Most of it is propaganda. Don't trust the New York Times. The rest of the media may be fine but don't trust the New York Times," he said. 

The real Mansour, a former civil aviation minister during Taliban rule, is a senior member of the Taliban's ruling council in the Pakistani city of Quetta. That council, or shura, is run by Taliban leader Mullah Mohammad Omar. 

If true, the claims that he was not really involved would be a blow to the Afghan government's push to find a political resolution to the nine-year-old war. It also raised questions about the credibility of some NATO officials who have said they facilitated contacts between Taliban figures and Afghan officials. 

According to the reports, the impostor met with Afghan and NATO officials three times -- including once with Karzai -- before they discovered he was not Mansour. 

Mansour was a well-known Taliban leader and had a high profile job in the movement's Cabinet. 

It is not clear why officials would have had such a difficult time identifying him. There are a number of former Taliban in parliament and in the 70-member High Peace Council recently formed by Karzai to find a political solution to the insurgency. It was reported that the man was believed to be a shopkeeper in Quetta. 

Although quite senior in the Quetta Shura, Mansour was not promoted to second-in-command of the Quetta shura following last February's arrest in Pakistan of Abdul Ghani Baradar. The Afghan Taliban's No. 2 leader was arrested in a joint raid with the CIA. 

Mansour was passed over in favor for Maulvi Zakir Qayyum -- a former Guantanamo detainee. Released into Afghan custody in 2007, Qayyum was freed four months later and rejoined the Taliban. 

In Pakistan last week President Obama's special representative to Afghanistan and Pakistan, Richard Holbrooke, played down reports about that senior Taliban leaders were holding talks with the Afghan government. 

The Associated Press contributed to this report.