ATLANTA -- Led by former president Jimmy Carter, thousands of moderate and liberal Baptists prayed and held hands across a massive exhibit hall Wednesday, trying to overcome racial and theological divisions and challenge conservative Southern Baptist dominance of their tradition.

The meeting, "Celebration of a New Baptist Covenant," included four major black denominations, Baptists from throughout North America and former members of the Southern Baptist Convention upset by its conservative views and ties to the religious right.

More than 10,000 participants are expected over three days.

In his opening address, Carter, a longtime Bible teacher at his Plains, Ga., church, called the gathering "the most momentous event in my religious life."

He repeatedly asked the audience to keep the event free of criticism of others.

"What is the prevailing image of Christians today?" Carter said. "It's the image of divisions among brothers and sisters of Christ as we struggle for authority or argue about the interpretation of individual verses in the Holy Scripture."

He called animosity among Christians from all traditions "a cancer metastasizing in the body of Christ."

The former president insisted the meeting was strictly religious, not political. It is being held just days before Feb. 5, when 24 states will hold presidential primaries or caucuses.

Former vice president Al Gore and former president Bill Clinton are among the major speakers. Earlier in the day, at a separate meeting of the black Baptist groups, senators Barack Obama and Hillary Rodham Clinton spoke about their presidential candidacies.

The black Baptists ended their meeting early so they could join the Carter-led event, which critics have dismissed as little more than a Democratic rally. The Rev. William Shaw, president of the National Baptist Convention USA Inc., the largest of the black denominations, said, "This time was set without any reference to the political calendar."

The meeting involves 30 Baptist groups that represent millions of people and span a range of theological and political beliefs. Many oppose abortion and same-sex marriage and ordain only men. However, they all heavily emphasize Scripture on social justice -- a major focus of the gathering.

"What we do as Baptists in this movement is biblically centered," said the Rev. Jimmy Allen, an organizer of the event. Allen served as the Southern Baptist president just before conservatives took control of the denomination waging a bitter fight over biblical inerrancy that lasted through the 1970s and 1980s.

Carter severed ties in 2000 with the convention because of what he called its "increasingly rigid" beliefs. He said Wednesday that he has been communicating with the current Southern Baptist president, the Rev. Frank Page, who has said that he "assured President Carter of my prayers" for the meeting despite some doubts about its purpose.

With 16.3 million members, the Southern Baptist Convention is not only the largest U.S. Baptist group, but also the largest Protestant denomination in the country.

Northern and Southern Baptists split in 1845, when Northerners said they wouldn't support missionaries who were slaveholders. Black Baptists generally formed their own denominations and had their own splits over civil rights strategies and other issues.

Several speakers Wednesday invoked the Rev. Martin Luther King Jr. when describing why this meeting was so important. Bill Underwood, president of Mercer University in Macon, a sponsor of the event, said, "I think we are taking a step today on the long and difficult journey to one day achieving Dr. King's dream."