WASHINGTON — The Department of Homeland Security said Friday that it is ending the collective bargaining agreement with the tens of thousands of front-line employees at the Transportation Security Administration, marking a major effort to dismantle union protections under the Trump administration. The TSA union called it on “unprovoked attack” and vowed to fight it.

The department, in a statement announcing the termination, criticized the union whose staffers are responsible for keeping weapons off airplanes and protecting air travel. The department said poor performers were being allowed to stay on the job and the agreement was hindering the ability of the organization “to safeguard our transportation systems and keep Americans safe.”

The American Federation of Government Employees is the union representing the TSA workers. The federation and the TSA’s then-administrator, David Pekoske, signed the collective bargaining agreement in May 2024. It came amid a push by Homeland Security to improve the pay for the front-line workers, whose pay has historically lagged that of other government employees.

President Donald Trump’s administration pushed out Pekoske on Inauguration Day. The TSA does not currently have an administrator or a deputy administrator.

The union said Homeland Security Secretary Kristi Noem and the Trump administration are violating the right of staffers to join a union. It also said the reasons the administration had given for the decision — specifically its criticisms of union activity — were “completely fabricated.”

AFGE represents about 800,000 federal government workers across the country.