The U.S. Department of Justice filed a federal lawsuit against the state of Connecticut, Gov. Ned Lamont and Attorney General William Tong on Friday over a new state law that prohibits federal agents from wearing masks and requires them to display identification when operating in the state.

The law, passed this spring by the Connecticut General Assembly and signed into law by Governor Ned Lamont, establishes “protected areas” — including schools, hospitals, social service agency facilities and houses of worship — where people cannot be arrested solely on the basis of a civil offense, such as an immigration violation. It prohibits law enforcement officers from wearing masks while on duty. It bans former federal law enforcement officers who were found to be guilty of misconduct or retired during an investigation from being hired by Connecticut state or local police, and it requires police officers to complete 480 hours of training before they can be hired by state agencies.

The federal government called the law “blatantly unconstitutional,” saying that the state has no authority to tell federal agents what they can and cannot do. The government argues that the law goes against the Supremacy Clause of the U.S. Constitution, which says that when state and federal laws clash, federal laws override those of the states.

Attorney General Tong said in a statement Monday that the new law was “fully lawful and necessary to protect public safety.”