U.S. federal agents stand guard while blocking a road leading to an agricultural facility where U.S. federal agents and immigration officers carried out an operation, in Camarillo, California, U.S., July 10, 2025. REUTERS/Daniel Cole

By Jasper Ward

WASHINGTON (Reuters) -The U.S. Department of Justice on Monday filed a lawsuit challenging California's ban on federal law enforcement officers wearing masks while on duty.

California Governor Gavin Newsom signed legislation in September prohibiting masking by local and federal law enforcement officers amid increased immigration enforcement efforts in the state.

The Justice Department said it does not plan to comply with the state law as it violates the U.S. Constitution's intergovernmental immunity doctrine and poses new legal liabilities for federal officers.

"Law enforcement officers thus face a real threat of criminal liability from state officials who have made clear their intent to target federal officers and disrupt federal law enforcement activities, including federal immigration enforcement," the department said in the lawsuit.

California Attorney General Rob Bonta said he was reviewing the lawsuit and Diana Crofts-Pelayo, a spokesperson for Newsom, said the state would see the Justice Department in court.

"It’s problematic when Californians can’t tell the difference between a law enforcement officer who is charged with protecting them and a criminal who is attempting to cause them harm," Bonta said in a statement.

The California law, the first of its kind in the U.S., was signed amid President Donald Trump's deployment of National Guard troops to Los Angeles during protests over immigration enforcement operations.

(Reporting by Maiya Keidan and Jasper Ward; Editing by Caitlin Webber, Rod Nickel and Stephen Coates)