(CNN) -- Scotland's Roman Catholic archbishop is contesting accusations of "inappropriate behavior" with priests, claims leveled as Cardinal Keith O'Brien prepares to join the conclave that will choose a new pope.
British newspaper The Observer reported Sunday that three priests and one former priest have leveled allegations against O'Brien that date back 30 years. The Observer did not recount details of the claims or identify any of O'Brien's accusers, but said one of the priests alleged "that the cardinal developed an inappropriate relationship with him."
O'Brien did not attend Mass at St. Mary's Cathedral in Edinburgh on Sunday, but the Scottish Catholic Media Office told CNN that the cardinal "contests these claims and is taking legal advice."
His accusers took their complaints to the Vatican representative in Britain and demanded O'Brien's resignation, The Observer reported. At the Vatican, Father Federico Lombardi, a spokesman for the church, told reporters that Pope Benedict XVI has been informed of the allegations.
The Irish-born O'Brien is scheduled to retire on St. Patrick's Day, his 75th birthday. But in a message to the Archdiocese of St. Andrews and Edinburgh last Sunday, he said he expected to take part as the College of Cardinals gathers in Rome to pick a successor to Benedict, who has led the worldwide church since 2005.
The accusations against O'Brien follow a buzz in Italian media about claims that gay clergy may have made themselves vulnerable to blackmail by male prostitutes, setting off speculation that a brewing scandal may have triggered Benedict's resignation. The Vatican vehemently denied the allegations Saturday, with Secretary of State Tarcisio Bertone criticizing a rash of "often unverified, unverifiable or completely false news stories" as the cardinals prepare for their conclave.
Benedict announced his resignation on February 11, saying that at 85, he was too weak to continue his duties. He leaves the papacy on Thursday, becoming the first pope to step down since 1415.
CNN's Hada Messia and Per Nyberg contributed to this report.