The U.S. 9th Circuit Court of Appeals today struck down as unconstitutional California's Prop 8, which banned same-sex marriage, the Associated Press reports.

The ruling by the three-judge panel is likely to be appealed to the U.S. Supreme Court.

REACTION: Voices weigh in on Prop 8 ruling

The court in San Francisco ruled 2-1 that a lower court judge interpreted the U.S. Constitution correctly in 2010 when he declared the ban, known as Proposition 8, to be a violation of the civil rights of gays and lesbians.

The measure, which passed with 52% of the vote in 2008, outlawed same-sex unions just five months after they had become legal in the state.

It was unclear when gay marriages might resume in California. Lawyers for Proposition 8 sponsors and for two couples who sued to overturn the ban have said they would appeal to the Supreme Court if they did not receive a favorable ruling from the 9th Circuit.

"Although the Constitution permits communities to enact most laws they believe to be desirable, it requires that there be at least a legitimate reason for the passage of a law that treats different classes of people differently. There was no such reason that Proposition 8 could have been enacted," the ruling states.