COLORADO SPRINGS, Colo. - The leader of the 30-million-member National Association of Evangelicals, a vocal opponent of the drive for same-sex marriage, resigned Thursday after being accused of paying for sex with a man in monthly trysts over the past three years.

The Rev. Ted Haggard, a married father of five who has been called one of the most influential evangelical Christians in the nation, denied the allegations. His accuser refused to share voice mails that he said backed up his claim.

Haggard also stepped aside as head of his 14,000-member New Life Church while a church panel investigates, saying he could "not continue to minister under the cloud created by the accusations."

The investigation came after a 49-year-old man told a Denver radio station that Haggard paid him to have sex.

Haggard denied the allegations in an interview with KUSA-TV late Wednesday.

In a written statement, Haggard said: "I am voluntarily stepping aside from leadership so that the overseer process can be allowed to proceed with integrity. I hope to be able to discuss this matter in more detail at a later date. In the interim, I will seek both spiritual advice and guidance."

Haggard, a 1978 graduate of Oral Roberts University, was appointed president of the association in March 2003 and has been called one of the most influential evangelical Christians in the nation.

The allegations come as voters in Colorado and seven other states get ready to decide Tuesday on amendments banning gay marriage. Besides the proposed ban on the Colorado ballot, a separate measure would establish the legality of domestic partnerships providing same-sex couples with many of the rights of married couples.

Mike Jones, 49, of Denver, said he decided to go public with his allegations because of the political fight. Jones, who said he is gay, said he was upset when he discovered Haggard and his church had publicly opposed same-sex marriage.

"It made me angry that here's someone preaching about gay marriage and going behind the scenes having gay sex," said Jones, who added that he isn't working for any political group.

Jones, whose allegations were first aired on KHOW-AM in Denver, claimed Haggard paid him to have sex nearly every month over three years. Jones also said Haggard snorted methamphetamine before their sexual encounters to heighten his experience.

Jones said that he had advertised himself as an escort on the Internet and that a man who called himself Art contacted him. Jones said he later saw the man on television identified as Haggard.