The Rev. Ted Haggard, the former president of the National Association of Evangelicals and one of the nation’s most influential Christian leaders, admitted today that he had purchased the illegal drug methamphetamine from a gay escort in Denver, but denied that he ever had sex with the man.

Mr. Haggard resigned as president of the evangelical association and stepped aside as senior pastor of the New Life mega-church in Colorado Springs, Colo., on Thursday after Michael Forest Jones, a self-described former gay prostitute, accused him of having a sexual affair for three years and using the drug, commonly known as crystal meth, during those encounters.

Earlier, in an e-mail message sent to parishioners and obtained by local news media, Ross Parsley, the acting pastor of the New Life Church said, “It is important for you to know that he confessed to the overseers that some of the accusations against him are true.”

Speaking to the Denver television station KUSA outside his house in Colorado Springs today, Mr. Haggard said a Denver hotel referred him to Mr. Jones for the purpose of getting a massage. He said he met with Mr. Jones and bought the drug. “I was tempted, I bought it, but I did not use it,” he said today. The station posted the video interview on its Web site.

He said he threw the drug out shortly after buying it. “I never kept it very long because it was wrong,” he said.

Asked if he engaged in sex with Mr. Jones, he said, “No I did not.” He also said he never used the drug with Mr. Jones as Mr. Jones has claimed.

Mr. Haggard, 50, who is married and has five children, has consistently denied the sex accusation, saying in a television interview: “I am steady with my wife. I’m faithful to my wife.”

He also had said he had never met the man making the accusation.

In his message, Mr. Parsley said Mr. Haggard “has willingly and humbly submitted to the board of overseers and will remain on administrative leave during the course of the investigation.”

On Thursday, Mr. 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.”

The Rev. Richard Cizik, vice president for governmental affairs at the evangelical association, said the group’s 15-member executive board would meet today to decide whether to accept the resignation.

The evangelical association states on its Web site that homosexual sex is condemned by Scripture, and Mr. Haggard has advocated passage of an amendment to the United States Constitution to ban same-sex marriage.

Mr. Jones, 49, told KUSA that Mr. Haggard had paid him for sex over the last three years, and that he had methamphetamine several times.

“People may look at me and think what I’ve done is immoral,” Mr. Jones, who said he is no longer a prostitute, told KUSA. “But I think I had to do the moral thing in my mind, and that is expose someone who is preaching one thing and doing the opposite behind everybody’s back.”

Mr. Jones took a polygraph examination in connection with other interviews and partially failed, local broadcasters said. They said the examiner said he would like to do a re-test because Mr. Jones was exhausted at the time of the first test.

Mr. Haggard said in a lengthy interview with KUSA that he had never used drugs of any kind and that he did not smoke or drink alcohol.

Mr. Haggard has been a supporter of an amendment to the state’s Constitution banning same-sex marriage, on which Coloradans will vote next week. He told KUSA that the accusations might have been politically motivated.

“It made me angry that here’s someone preaching about gay marriage and going behind the scenes having gay sex,” Mr. Jones said.