A charismatic Bosnian priest who was played by Martin Sheen in a movie has been barred from leading a prayer service this evening at the Basilica of the National Shrine of the Immaculate Conception following allegations of disobedience and sexual abuse.

Organizers said they had expected more than 3,000 people to turn out to hear the Rev. Jozo Zovko, a prominent supporter of claims that the Virgin Mary has appeared to six teenagers in the Bosnian village of Medjugorje, where he was once a pastor.

The apparitions at Medjugorje, first reported in 1981, are a subject of passionate debate among Catholics.

Many pilgrims consider the town a holy site, while critics say the purported miracles are nothing more than a money-making scam. Sheen played Zovko in the 1995 film "Gospa" ("Madonna"), a fictionalized biography of the priest.

The Rev. Walter Rossi, director of pilgrimages at the National Shrine, said officials there decided to prohibit Zovko from saying Mass and speaking publicly about the Virgin Mary after they received a letter from his bishop describing Zovko as a "disobedient Franciscan" who has been stripped of "every faculty" to serve in public ministry since 1989.

The letter from Ratko Peric, the bishop of Mostar, did not explain the reasons for Zovko's original censure, which was imposed by Peric's predecessor, now deceased. But the letter said that despite the loss of his faculties, Zovko had continued to hear confessions, a violation of church law that resulted in further penalties in 1994.

"Though unaware of what precipitated this action, or of any credible allegations against Father Zovko, the National Shrine must abide by Canon Law," Peter Sonski, a spokesman for the Shrine, said in a written statement. "Since he is under censure and may not exercise his priestly ministry, Father Zovko cannot take part in this event as planned."

The prayer service's organizer, the Rev. Gerard A. Petta, said the allegations were "political" and stemmed in part from opposition among Bosnian bishops to recognizing the Medjugorje apparitions as genuine.

According to the 1998 book "The Medjugorje Deception" by E. Michael Jones, Zovko has been accused of sexually molesting several women making the pilgrimage there. The allegation was repeated in a Nov. 14 article in the Wanderer, a Catholic weekly, and in leaflets handed out by protesters at appearances by Zovko in Boston this week.

Petta said Zovko would not be available for comment, and attempts to reach Zovko through other supporters were unsuccessful.

"There is no credibility at all to the allegations of sexual abuse. It just doesn't exist," Petta said, adding that Zovko is "a holy man" and a "very, very charismatic and powerful priest."

Zovko, who began a speaking tour of the United States on Nov. 5, has not been blocked from appearing anywhere but Washington, which was to be his final stop, according to Petta. He said the prayer service would still take place this evening, but that Zovko's Bosnian translator would speak in his place.