Britain's senior Catholic cleric, Cardinal Keith O'Brien, has resigned after denying claims of "inappropriate acts".
The UK's Observer newspaper reported on Sunday that three priests and a former cleric had accused Cardinal Keith O'Brien of impropriety.
The 75-year-old head of the Scottish church has rejected the claims.
In a statement released on Monday, O'Brien said Pope Benedict XVI, who himself announced his retirement earlier this month, had accepted his resignation.
"The Holy Father has now decided that my resignation will take effect today, February 25," he said. "For any good I have been able to do, I thank God. For any failures, I apologise to all whom I have offended."
He also said he would not attend the papal conclave, the meeting to elect the next pope, which will be held after the pope resigns on February 28.
"I will not join them for this conclave in person," O'Brien said."I do not wish media attention in Rome to be focussed on me - but rather on Pope Benedict XVI and on his successor."
Benedict, only the second pope to resign of his own free will in the church's 2,000-year history, changed church laws on Monday so that the conclave can begin earlier, the Vatican said.
Instead of having to wait 15 days until after the papacy becomes vacant to vote, the conclave can now start before March 15.
The Observer newspaper reported that the four accusers filed their complaints about O'Brien before Vatican ambassador Antonio Mennini.
In one instance, one of the complainants alleged that O'Brien made the advances after a late-night drinking session.
A spokesman for the cardinal said the allegations have been contested, according to the report.
The allegations against O'Brien came as Roger Mahony, another cardinal, was urged not to take part in the selection of Benedict's successor after being accused of being complicit in protecting abusive priests while he was head of Los Angeles archdiocese, the largest in the US.
In another development on Monday, the Vatican said a report into papal documents leaked by the pope's butler in the so-called "Vatileaks scandal" last year will remain confidential and only be shown to his successor.
"The Holy Father has decided that the facts of this investigation, the contents of which are known only to Himself, will be made available exclusively to the new Pontiff," the Vatican said in a statement.
Some Italian media had called for the report to be made public ahead of the conclave that will choose the next pope.