KABUL- Afghanistan's president is denying he met with a senior Taliban leader. Hamid Karzai told a news conference on Tuesday that he never met Akhtar Mohammad Mansour. He says the ranking Taliban did not travel from Pakistan to Kabul. Karzai however, didn't say if the man reportedly involved in talks with the Afghan government was an impostor. He said that the overall reports were not acceptable but did not elaborate further. An Afghan familiar with reconciliation efforts between insurgents and the Afghan government says a man involved in the talks who claimed to be Mansour was an impostor. The Afghan spoke on condition of anonymity so as not to jeopardize his contacts with both sides. The New York Times said on Tuesday that a man it had described as a "Taliban leader" who had taken part in "secret peace talks" with the Afghan government was in fact an impostor. The newspaper said the man had held three meetings with NATO and Afghan officials but that US officials had confirmed on Monday "they had given up hope" he was the leader identified as Mullah Akhtar Muhammad Mansour. "The fake Taliban leader even met with President Hamid Karzai, having been flown to Kabul on a NATO aircraft and ushered into the presidential palace," the newspaper said, again citing unidentified officials.