Georgia's Republican Gov. Brian Kemp has signed legislation banning abortions once a fetal heartbeat can be detected. That can be as early as six weeks, before many women know they're pregnant.
The signing Tuesday morning caps weeks of protests at the state Capitol and marks the beginning of a possibly costly legal battle.
"As you all know, Georgia is a state that values life. We protect the innocent. We champion the vulnerable. We stand up and speak for those unable to speak for themselves."
ACLU of Georgia legal director Sean Young said the new law is unconstitutional and the ACLU would challenge it in court.
"Some may challenge it in a court of law. But our job is to do what is right, not what is easy. We are called to be strong and courageous and we will not back now. We will always continue to fight for life."
Anti-abortion activists and lawmakers across the country have been energized by the new conservative majority on the U.S. Supreme Court.
Several GOP-controlled states are pushing abortion bans in an attack on the high court's 1973 Roe v. Wade ruling that legalized abortion nationwide.
Similar bans have been signed into law in Mississippi, Kentucky and Ohio, and are being considered elsewhere.
(The Associated Press contributed to this report.)
