The Supreme Court on Thursday declined to put on hold a new Illinois law that would ban high-power semiautomatic weapons like the one used in the mass killing of seven people at a 2022 parade in a Chicago suburb.

The justices did not comment in refusing an emergency appeal from a gun rights group and others.

The law prohibits the possession, manufacture or sale of semiautomatic rifles and high-capacity magazines. It takes effect Jan. 1.