Illinois has banned the sale of many common kinds of semiautomatic guns with immediate effect in response to a massacre at an Independence Day parade in Highland Park last year and other mass shootings.
The new law, which Illinois Governor J B Pritzker signed on Tuesday evening, bans selling many kinds of weapons that automatically load the next bullet after a shot, including semiautomatic rifles and pistols with detachable magazines. The law lists dozens of popular gun brands made by US gun makers.
Rifles that hold more than 10 bullets and pistols that hold more than 15 are also banned, as are rapid-fire attachments and .50-caliber guns. People who already own such weapons will be able to keep them but must register them with the state police.
Eight other states and the District of Columbia have already enacted similar bans. Gun-owners rights groups say the bans violate the US Constitution's Second Amendment "right to keep and bear arms" and that many law-abiding Americans have such guns for self-defence, hunting and for sport.
"No Illinoisan, no matter their zip code, should have to go through life fearing their loved one could be the next in an ever-growing list of victims of mass shootings," Pritzker, a Democrat, said in a statement.
In signing the bill, he invoked the attack on the July 4 parade in Highland Park last year, in which a man with a semiautomatic rifle killed seven people and wounded dozens of others over the course of a few minutes.
Richard Pearson, executive director of the Illinois State Rifle Association, said the law affects nearly 2.5 million gun owners in the state and his group would sue to reverse the ban. "Challenge accepted," his statement said.
Brady, a national group advocating against gun violence, said the ban would save lives.