NEW YORK — The American Civil Liberties Union filed a lawsuit yesterday alleging that the federal government has improperly used taxpayer dollars to fund Christian activities in a nationwide program called the Silver Ring Thing that uses music and comedy skits to promote premarital abstinence among teens.

The Silver Ring Thing — which has held events in dozens of cities over the past five years — is an offshoot of the John Guest Evangelistic Team, a Christian ministry based in Sewickley, Pa. Since 2003, the program has received more than $1 million from the Department of Health and Human Services as part of the Bush administration’s initiative to expand abstinence-only education.

Though many of the grant recipients have religious affiliations, they are not supposed to use the federal money for religious proselytizing. The lawsuit, filed in federal court in Boston, alleges that the Silver Ring Thing crosses this line and uses grant money to encourage young people to commit themselves to Jesus Christ.

“The courts have repeatedly said taxpayer dollars cannot be used to promote religion,” said Julie Sternberg, an attorney with the ACLU’s Reproductive Freedom Project. “The Silver Ring Thing blatantly violates this principle.”

Chris Downing, a spokesman for the Department of Health and Human Services, said HHS doesn’t comment on pending litigation.

Denny Pattyn, the Silver Ring Thing’s founder and president, issued a statement describing the program as “faith-based” but asserting that the federal funds had been properly used at all times. The suit names only HHS officials, not the Silver Ring Thing, as defendants, and seeks to halt federal funding to the program.

In an interview two years ago with Agape Press, a conservative Christian news service, Pattyn was quoted as saying the federal funding “is a blessing, but also puts some restrictions on what the ministry can do with its sexual abstinence program.”

“We don’t ever want to take the gospel out of our message because we believe the power for abstinence is a changed heart, not a ring on a finger,” Pattyn was quoted as saying.

The Silver Ring Thing says more than 30,000 young people have committed themselves to premarital purity after attending the program’s three-hour multimedia presentations. In its latest newsletter, the program reports on the number of youths who “made commitments to Christ” at the conclusion of recent presentations — for example, 95 at a March event in Detroit, 65 at a February event in Immokalee, Fla.

The ACLU lawsuit says youths attending the presentations are given the opportunity to divide into secular and religious groups for the final portion of the event. The suit contends that students are encouraged to choose the religious option and to enroll in a Bible-based follow-up program — and it alleges that organizers make no effort to use the federal money only for secular purposes.

The suit also complains that the silver rings sold to youths who take the abstinence pledge are inscribed with a reference to a biblical verse which says, “God wants you to be holy, so you should keep clear of all sexual sin. Then each of you will control your own body and live in holiness and honor.”

In a previous lawsuit, the ACLU obtained a court order in Louisiana requiring the state to keep religion out of a taxpayer-funded abstinence education program. The ALCU is currently seeking to have the state held in contempt, alleging that religious material remains on the program’s official Web site.

Beyond the question of religion, there has been extensive debate over the effectiveness of abstinence-only education. Critics, including the ACLU, say there is no conclusive evidence that such programs work; the government and conservative groups defend abstinence as the only strategy guaranteed to protect a youth from unintended pregnancy and sexually transmitted disease.

In addition to its U.S. programs, the Silver Ring Thing has staged events overseas, notably in Britain and South Africa. It was the subject of a British Broadcasting Corp. news special last year entitled “American Virgins.”