VATICAN CITY -- The Vatican says American Archbishop Paul Marcinkus and two aides, charged with complicity in fraudulent bankruptcy, are immune from prosecution by Italy under a 58-year-old treaty, according to a Roman Catholic magazine.

A Vatican tribunal made the decision on the case on April 25 and has advised Milan judges who charged Marcinkus, president of the Vatican bank, and his aides, the weekly Il Sabato reported Wednesday.

Il Sabato said the Vatican argued that the three administered "a central organ of the Church" and thus are immune from prosecution by Italian authorities under a clause of the 1929 Lateran Treaties governing relations between the Vatican and the Italian state.

The tribunal also rejected the warrants and extradition requests against the three because the charges "are in part conjectural and are contradicted by some documents produced by the defense," the magazine said.

Italy's highest court of appeal is expected to decide shortly the validity of the charges lodged by the Milan investigators.

Marcinkus, 65, a native of Cicero, Ill., is considered the most powerful American in the Vatican. In addition to his bank president post, he was made governor of the Vatican city-state by Pope John Paul II.

The Ambrosiano bank crashed in 1982 with debts of $1.287 billion. The president at the time, Roberto Calvi, fled to London where his body was found hanging from scaffolding under the Thames River Blackfriars Bridge June 18, 1982.

The charges against Marcinkus and his aides were based on the Vatican bank's links with Calvi. The Vatican formally denied any liability in the Ambrosiano collapse, but in July 1984 it paid $240.9 million to bank creditors as a "goodwill gesture."