(CNN) -- The Presbyterian Church (U.S.A.) voted Thursday to allow pastors to marry same-sex couples in states where it is legal.

The church also voted, by an overwhelming majority, to change the language about marriage in the church constitution to "two persons" from a "man and a woman," according to More Light Presbyterians, a group that supports gay rights.

To take effect, that change would need to be approved by a majority of 172 local presbyteries, which have a year to vote, the church said in a statement.

However, starting Saturday, pastors can go ahead and begin marrying same-sex couples in the states that allow it, according to Toya Richards Jackson, a church spokeswoman.

"The church affirmed all its faithful members today. This vote is an answer to many prayers for the Church to recognize love between committed same-sex couples," said Alex McNeill, executive director at More Light Presbyterians.

"We will keep praying that the majority of our 172 presbyteries will confirm that all loving couples can turn to their churches when they are ready to be married."

Another Presbyterian group, the Presbyterian Lay Committee, protested the vote, saying the church "has committed an express repudiation of the Bible."

The group called for adherents to make their voices of opposition heard, and even withhold money from the church.

"The Presbyterian Lay Committee mourns these actions and calls on all Presbyterians to resist and protest them," the group said in a statement.

Close to half of the clergy in the Presbyterian Church (U.S.A.) work in areas where same-sex couples can legally marry.

In the U.S., same-sex marriage is legal in the District of Columbia and 19 states: California, Connecticut, Delaware, Hawaii, Illinois, Iowa, Maine, Maryland, Massachusetts, Minnesota, New Hampshire, New Jersey, New Mexico, New York, Oregon, Pennsylvania, Rhode Island, Vermont and Washington.

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CNN's Daniel Burke and Joe Sutton contributed to this report.