Warsaw: A Polish archbishop appointed last month by Pope Benedict faced calls to explain his past or resign after a newspaper yesterday published documents it said showed he was a communist informer.

The Pontiff named Stanislaw Wielgus on December 6 to succeed anti-communist Cardinal Jozef Glemp as archbishop of Warsaw, one of the most influential positions in Poland's church hierarchy. He is due to take the post during a mass on Sunday.

Last month, Wielgus denied allegations published in a right-wing newspaper that he spied and reported on dissidents for the feared communist secret police, saying he was the victim of a smear campaign.

He later admitted he had spoken to police agents but said he never filed a report.

Yesterday, Rzeczpospolita newspaper, one of Poland's most respected dailies, ran a front-page article detailing what it described as 20 years of close cooperation between Wielgus and communist police based on files from national archives.

"Wielgus should ask for [Sunday's] ceremony to be postponed so he can clear up these charges," the paper wrote on its editorial page.

There was no immediate comment from Wielgus on the latest allegations.

In the 1980s, the church in staunchly Catholic Poland supported the pro-democracy Solidarity movement and, backed by Polish-born Pope John Paul II, played a crucial role in bringing down communism.

Wielgus also came under fire from his colleagues in the Catholic church. Some called on him to resign while others demanded an immediate explanation.