The Justice Department filed a lawsuit on Tuesday against Arizona to challenge a new state law intended to combat illegal immigration, arguing that it would undermine the federal government’s pursuit of terrorists, gang members and other criminal immigrants.

The suit, filed in federal court in Phoenix, had been expected since mid-June, when Obama administration officials first disclosed they would contest the Arizona law, adding to several other suits seeking to have courts strike it down.

The federal government added its weight to the core argument in those suits, which contend that the Arizona law usurps powers to control immigration reserved for federal authorities. The main suit was brought by the American Civil Liberties Union, the Mexican American Legal Defense and Educational Fund and other civil rights groups.

The Justice Department argues the law would divert federal and local law enforcement officers by making them focus on people who may not have committed crimes, and by causing the “detention and harassment of authorized visitors, immigrants and citizens.”