LOS ANGELES, July 22 (Xinhua) -- More than 140 employees of the U.S. National Science Foundation (NSF) have signed a letter condemning the Trump administration's policies and actions on science that they say have undermined one of the country's leading scientific funding institutions.

In a letter addressed to Zoe Lofgren, ranking member of the U.S. House of Representatives' Committee on Science, Space, and Technology, on Monday, the scientists accuse the Trump administration of abruptly terminating staff, withholding critical research funds, and drastically cutting the agency's budget.

Due to concerns about retaliation, all but one of the employees' signatures have been withheld.

The signatories expressed concerns over a series of "politically motivated" and "legally questionable" actions by the Trump administration that threaten the integrity of the NSF and undermine the civil service protection guaranteed under federal law.

The letter called on the U.S. Congress to defend the NSF's mission and workforce, reaffirm its scientific independence, and maintain support for research vital to national prosperity and security.

This statement follows similar protest letters released last month by scientists and staff at the National Institutes of Health and employees at the Environmental Protection Agency, as well as the recent Voyager Declaration signed by current and former scientists of the National Aeronautics and Space Administration.

Experts say these collective actions represent an unprecedented wave of dissent among U.S. federal scientific employees. ■