Maryland has joined a coalition of states to sue the Trump administration over its plan to allow the sale of forced-reset triggers that make semiautomatic rifles fire more rapidly and return devices already seized to their owners.

The suit announced Monday argues that returning the triggers would violate federal law, pose a threat to residents and law enforcement and worsen gun violence. It was filed in federal court in Maryland.

“Forced reset triggers turn semi-automatic firearms into weapons of war capable of inflicting devastating impacts on Maryland communities,” said Maryland Attorney General Anthony Brown in a release. “The Trump administration’s decision to send these previously seized firearms back to Maryland, where they are illegal, makes our neighbors and children more vulnerable to mass shootings.”

There had been several legal battles over the devices, which replace the typical trigger on an AR-15-style rifle. The Biden administration had previously argued the triggers qualify as machine guns under federal law because constant finger pressure on the triggers will keep a rifle firing, essentially creating an illegal machine gun.

Rare Breed Triggers, the maker of the devices, had argued that the Bureau of Alcohol, Tobacco, Firearms and Explosives was wrong in its classification and ignored demands to stop selling the triggers before being sued by the Biden administration.

The Justice Department reached a deal announced last month to allow the sale of forced-reset triggers with Rare Breed Triggers, which was previously represented by David Warrington, Trump’s current White House counsel.

Under the settlement, Rare Breed Triggers agreed not to develop such devices to be used on handguns, according to the Justice Department. The settlement requires the ATF to return triggers that it had seized or that owners had voluntarily surrendered to the government.

The states’ lawsuit is being led by the attorneys general of Maryland, Delaware and New Jersey. Other states involved are Colorado, Hawaii, Illinois, Maine, Massachusetts, Michigan, Minnesota, Nevada, Oregon, Rhode Island, Vermont, Washington, along with the District of Columbia.