JACKSON, Miss. (AP) — Mississippi Gov. Phil Bryant on Thursday signed one of the strictest abortion laws in the nation — a measure that bans most abortions once a fetal heartbeat can be detected, about six weeks into pregnancy.

Bryant's action came despite a federal judge's ruling last year that struck down a less-restrictive law limiting abortions in the state. The New York-based Center for Reproductive Rights called the new measure "cruel and clearly unconstitutional" and said it would sue Mississippi to try to block the law from taking effect on July 1.

After a bill signing ceremony at the...