The union, chaired by Dr. Kurt Gottfried, Emeritus Professor of Physics at Cornell University, said more than 4,000 scientists, including 48 Nobel laureates, had joined the call for "restoration of scientific integrity in federal policymaking."

"I don't think one should simply assume that the problem ... will go away if there is a new administration in office," Gottfried told reporters in a telephone briefing.

"What is happening under this administration is a cultural change. We have to address this cultural change and fix it."

Gottfried's group previously leveled similar charges against the Bush administration in February.

Two recently appointed members to the National Advisory Council for Human Genome Research, Dr. Richard Myers of Stanford University in California and Dr. George Weinstock of Baylor College of Medicine in Texas, said they had been asked inappropriate questions when they were nominated.

Weinstock said a staffer at the Health and Human Services Department called to ask "leading political questions."

"There is no doubt in my mind that these questions represented a political litmus test," he said in a statement.

Myers said he received a similar call in which he was asked about his opinion of embryonic stem cell research, which the White House opposes.

"Then the staffer asked questions that really shocked me," Myers is quoted as saying in the report. "She wanted to know what I thought about President Bush: Did I like him, what did I think of the job he was doing."

Dr. Gerald Keusch, former Associate Director for International Research at NIH, said NIH staffers in Bethesda, Maryland, were being forced to put in travel requests to visit the offices of the Pan American Health Organization "just a Metro trip away" in downtown Washington, D.C. "You are now required to submit a travel request six weeks ahead of time," said Keusch, who resigned last year.

"These are increasing bits of evidence of attempts at control over the way the business of science, the open communication between scientists, is being conducted."

White House science adviser Dr. John Marburger and HHS spokesman Bill Pierce have denied the administration is distorting science. Pierce says HHS is seeking a diversity of opinions.

But Robert Paine, an ecologist at University of Washington who chaired an advisory panel on endangered salmon and trout, said his team was warned by the government to remove facts that undermined policy.

"We were told to strip out specific scientific recommendations or see our report end up in a drawer," Paine said.