Some 1,900 leading researchers accused the Trump administration in an open letter on Monday of conducting a “wholesale assault on U.S. science” that could set back research by decades and that threatens the health and safety of Americans.

In a letter, several members of the National Academies of Sciences, Engineering, and Medicine warn Trump’s overhaul of U.S. science has created a “climate of fear.”

Nearly 2,000 members of the National Academies called on the Trump administration to halt its “wholesale assault on U.S. science" in an open letter.