The revelations emerged a day after the UN published a hotly contested report into crimes committed by armed groups in the eastern Democratic Republic Congo at the end of the 1990s.
A UN report "on crimes committed in Afghanistan between April 1978 and December 2001 was deliberately suppressed by the United Nations for political reasons", Le Temps said after obtaining a copy of the 300-page document.
"The famous 'mapping report', which was finalised in December 2004 after a year of work, was supposed to be published in January 2005," the newspaper said. "It was not and, after a succession of other reports, was forgotten."
The report covered the tumultuous period from the military coup in April 1978 through the Soviet invasion, the rise and fall of the Taliban up against the US-led coalition force. It accused "Soviets, communist chiefs, Islamist militants and even American forces" of having "taken part to varying degrees in atrocities", the newspaper said, citing torture, summary executions, mass rape and the use of child warriors.
One of the report's three authors, American Barnett Rubin, said that the UN must have decided not to publish it "at the request of (Afghan President Hamid) Karzai because it mentioned people still in the Afghan government", the report said.
But in an email to AFP yesterday, Rubin added that the report contained previously published material and denied that any "secrets" were being hidden from the public. "The report was a compilation of previously published reports. It contained no revelations based on new research. Every statement in the report is already part of the public record," Rubin wrote.
"No 'secrets' are being suppressed. The report has been freely available on the Internet for over a year."