NEW YORK, Jan. 28 (Xinhuanet) -- A top scientist at NASA said the Bush administration has tried to muzzle him since he gave a lecture in December calling for prompt reductions in emissions of greenhouse gas, the New York Times said on Saturday.

    The scientist, James E. Hansen, longtime director of NASA's Goddard Institute for Space Studies, said in an interview that the officials at NASA headquarters had ordered the public affairs staff to review his lectures, papers, postings on the Goddard Web site and requests for interviews from journalists.

    "They feel their job is to be this censor of information going out to the public," the scientist was quoted by the newspaper as saying, adding that he planned to ignore the restrictions.

    However, a NASA spokesman denied any effort to hush Hansen, theNew York Times said. "That's not the way we operate here at NASA,"said Dean Acosta, deputy assistant administrator for public affairs at NASA.

    "We promote openness and we speak with the facts."

    The spokesman said the restrictions applied to all NASA personnel who could be seen by the public as speaking for the agency. But he added that while government scientists were free to discuss scientific findings, policy statements should be left to policy makers and appointed spokesmen.

    Hansen, 63, a physicist who joined the space agency in 1967, isan authority on climate who directs efforts to simulate the global climate on computers at Manhattan's Goddard Institute.

    Since 1988, he has been issuing public warnings about the long-term threat from heat-trapping emissions, dominated by carbon dioxide, that are a byproduct of burning coal, oil and other fossil fuels.

    The Times said Hansen said he fell out of favor with the White House in 2004 after a University of Iowa speech ahead of the presidential election in which he complained that government climate scientists were being muzzled, adding that he planned to vote for Democratic nominee John Kerry.Enditem