WARSAW, Poland — The archbishop of Warsaw resigned yesterday, minutes before he was due to celebrate his inaugural Mass, after confessing that he had been an informant for Poland’s communist-era secret police.

Monsignor Stanislaw Wielgus, who was appointed archbishop of the Polish capital last Friday, tearfully read out his resignation to cries of disbelief from the congregation in Warsaw Cathedral.

“Stay with us,” several worshippers shouted, despite repeated calls for quiet. Outside, many of the conservative supporters of Monsignor Wielgus jostled and exchanged insults with a handful of demonstrators opposing the archbishop’s appointment.

After initially denying that he had any links with the Cold War secret services, Monsignor Wielgus said last Friday, after two independent commissions condemned him, that he had been a collaborator.

His accusers say he was first approached when studying at Lublin University in 1967 and that he was referred to by his spy masters as either Agent Grey or Adam Wisocki.

He was allegedly asked to keep tabs on the “anti-social activities” of other priests and was once asked to infiltrate the Polish office of Radio Free Europe, an assignment that he declined.

His dramatic resignation came after overnight talks between the Vatican and the Polish government. Previously, the Vatican had supported Monsignor Wielgus, declaring before Christmas that Pope Benedict had been “fully aware” of all the details of the priest’s past before making his choice.

However, the prospect of a split within the Polish Catholic Church finally convinced the Vatican to abandon its nominee on Saturday night.

The pope’s spokesman, the Reverend Federico Lombardi, said yesterday: “The behavior of Monsignor Wielgus in the former years of the communist regime in Poland has severely compromised his authority. The relinquishment of his position in Warsaw and the pope’s ready acceptance of his resignation appeared to be an adequate solution, despite his humble and moving request for a pardon.”

Just before the beginning of the service, the Vatican’s embassy in Poland issued a statement saying the pope had asked the former archbishop of Warsaw and a key figure in the country’s struggle against communist rule, Cardinal Jozef Glemp, to resume his role temporarily until “further decisions have been made.”

Inside the cathedral, there were chaotic scenes as Cardinal Glemp defended his colleague and suggested that he had not lost the support of the higher levels of the Polish church.

Addressing hundreds of worshippers, he said the judgment against Monsignor Wielgus was based on “scraps of papers and documents” and added that, “This is not the kind of judgment we need.”

His remarks, in front of President Kaczynski of Poland, and the former private secretary of Pope John Paul II, Cardinal Stanislaw Dziwicsw, were frequently interrupted by applause.