Afghanistan's senior-most prosecutor who has complained that the attorney general and others are blocking corruption cases against high-ranking government officials says that he was fired by Afghan President Hamid Karzai, The New York Times reported Sunday. Fazel Ahmed Faqiryar, a former deputy attorney general, told the Times in an interview that investigations of more than two dozen senior Afghan officials -- including cabinet ministers, ambassadors and provincial governors -- were being held up or blocked outright by Karzai, Attorney General Mohammed Ishaq Aloko and others. The account has been largely corroborated in interviews with five Western officials familiar with the cases, the report said. These officials say Karzai and others in his government have repeatedly thwarted prosecutions against senior Afghan government figures, The Times said. One US official, speaking on condition of anonymity, said that Afghan prosecutors had prepared several cases against officials suspected of corruption, but that Karzai was "stalling and stalling and stalling," the paper noted. "We propose investigations, detentions and prosecutions of high government officials, but we cannot resist him," Faqiryar is quoted as saying of Karzai. "He won?t sign anything. We have great, honest and professional prosecutors here, but we need support." This month, Karzai intervened to stop the prosecution of one of his closest aides, Mohammed Zia Salehi, who investigators say had been wiretapped demanding a bribe from another Afghan, The Times said. The paper pointed out that Karzai's chief of staff disputed Faqiryar's characterization of the president's involvement, saying that the president had instructed the prosecutors to move cases forward "appropriately". "I strongly deny that the president has been in any way obstructing the investigations of these cases," the chief of staff, Umer Daudzai, is quoted as saying. "On the contrary, he has done his bit in all these cases, and it is his job to make sure that the justice is not politicized. And, unfortunately we see in some of these cases that it is politicized."