LITTLE ROCK, Ark. -- Arkansas' governor on Thursday approved a ban on a commonly used second-trimester abortion procedure -- restrictions that are expected to face a legal challenge.

Republican Gov. Asa Hutchinson signed into law a measure banning the procedure known as dilation and evacuation, which abortion-rights supporters contend is the safest and most common procedure used in second-trimester abortions.

Hutchinson signed the bill hours after it was approved by the majority- GOP Senate on a 25-6 vote. It won't take effect until later this year.

Hutchinson, who had promised abortion opponents earlier this week he would sign the ban into law, didn't issue a statement after approving the measure.

Arkansas Right to Life has called the prohibition its top legislative priority in Arkansas, and the group's president has called the procedure "barbaric."

"I think this is a humane bill. ... I think it does move us to a more compassionate society," Republican Sen. David Sanders, who co-sponsored the measure, told lawmakers before the vote.

The American Civil Liberties Union of Arkansas said the measure is unconstitutional.

"It's an empty gesture that's going to cost the state tens of thousands of dollars in litigation fees and costs," said Rita Sklar, executive director of the ACLU of Arkansas.

Similar bans are in effect in Mississippi and West Virginia. Bans in Alabama, Kansas, Louisiana and Oklahoma have been put on hold due to legal challenges.

The procedure was used in 683 of the 3,771 abortions performed in Arkansas in 2015, according to the state Department of Health.

The Arkansas law will take effect 90 days after the Legislature formally adjourns its 2017 session, which usually occurs in April or May.

The ban is part of a push by abortion opponents nationally and at statehouses around the country with Republicans in control of the White House and Congress.