The newly appointed archbishop of Warsaw resigned on Sunday, less than an hour before his scheduled installation, after admitting he had co-operated with Poland's communist-era secret police.
Stanislaw Wielgus announced his decision at Warsaw's St. John's Cathedral, packed with worshippers gathered for a mass that was to have marked his formal installation. The congregation included President Lech Kaczynski.
Though some in the congregation, including Kaczynski, applauded the announcement, others shouted that Wielgus was welcome to stay.
Stanislaw Wielgus admitted he had informed against fellow clerics.
(Czarek Sokolowski/Associated Press)
In his resignation letter to Pope Benedict XVI, he said his past actions had "gravely compromised his authority" in the Roman Catholic homeland of the late Pope John Paul II.
The admission that he collaborated with the former communist regime, which ended in 1989, is a major embarrassment for the Vatican and the powerful Polish Catholic Church.
His resignation reportedly came at the request of Pope Benedict, who appointed him just a month ago.
Wielgus, 67, is believed to have informed on fellow clerics for around 20 years, from the late 1960s, according to allegations raised in a Dec. 20 article by the weekly Gazeta Polska newspaper.
He initially denied any collaboration, but the scandal widened when church officials on Friday said that documents at a historical institute showed Wielgus had willingly co-operated with the secret services, and the Polish media intensified calls for his resignation.
Wielgus has since issued statements acknowledging that he signed an agreement in 1978 promising to co-operate with the security force in exchange for permission to leave Poland to study in West Germany.
However, he stressed that he did not inform on anyone or try to hurt anyone, and he expressed remorse for both his contacts with the secret police and his failure to be forthcoming from the beginning.
With files from the Associated Press
St. John's Cathedral, where the former Archbishop announced his resingation

Stanislaw Wielgus, the Archbishop of Warsaw, resigned yesterday after admitting to have worked for the secret police of Poland during the operation of the Communist government. At a mass in Warsaw Cathedral, the Archbishop was to have marked his formal installation. Instead, he tendered his resignation. The resignation came at the request of Pope Benedict XVI, who had appointed Wielgus one month previously. 

The reaction to the resignation is mixed. Polish President Lech Kaczyński, who attended the service, applauded the resignation. Wielgus' supporters gathered outside the cathedral, yelling "Stay with us". Those opposed to the Archbishop also gathered outside, carrying banners that said "non possumus" ("we cannot allow that").

Since the late 1960s, the former Archbishop spied on members of the Church for about 20 years. After the ''Gazeta Polska'' newspaper published allegations of his actions on December 20, Wielgus denied them. However, when church officials announced they had obtained documents showing that Wielgus had willingly co-operated with the secret services, he acknowledged that the accusations were true. 
There is some suspicion that the documents were leaked by communists, in retribution for the Catholic Church's role in the fall of European communism.

A poll, conducted by the TNS OBOP Institute and published January 5 in the Polish daily ''Dziennik Polska-Europa-Świat'', revealed that 26% supported the Archbishop's immediate resignation, 41% thought that he would have to resign "after some explanations", 20% believed that he should keep his position, and 13% had "no opinion".

Cardinal Józef Glemp will retain the position of apostolic administrator until a replacement is chosen.