More than 1,900 scientists and engineers have signed a letter saying they “see real danger in this moment” as the Trump administration slashes federal support for scientific research.

“Wise investments by the US government have built up the nation’s research enterprise, making it the envy of the world,” says the open letter published on Monday. “Astoundingly, the Trump administration is destabilizing this enterprise by gutting funding for research, firing thousands of scientists, removing public access to scientific data, and pressuring researchers to alter or abandon their work on ideological grounds.”

The letter was penned by members of the National Academies of Sciences, Engineering, and Medicine, which was created by Congress under President Abraham Lincoln to advise policymakers. Each person signed to express their individual support rather than as representatives of the universities and research institutions with which they are affiliated.

They accuse the Trump administration of censorship through executive orders and funding threats meant to stop any initiatives the president and his close allies dislike, including efforts to address climate change and develop vaccines.

The White House didn’t immediately respond to The Verge’s request for comment.

“The quest for truth — the mission of science — requires that scientists freely explore new questions and report their findings honestly, independent of special interests,” the letter says. “The administration is engaging in censorship, destroying this independence.”

The US is at risk of losing an entire generation of scientists as a result, the signatories warn. More than 1,200 scientists are already thinking about leaving the US because of the Trump administration’s drastic actions, making up 75 percent of respondents in a separate poll by the journal Nature.

“A climate of fear has descended on the research community,” National Academies members write in the letter. “We are sending this SOS to sound a clear warning: the nation’s scientific enterprise is being decimated.”