ROME—A high-end prostitute says she has proof that she spent the night at Silvio Berlusconi’s Rome residence after a party that allegedly featured the prime minister’s wisecracks, his cabaret crooning and a bevy of sexy women.

Berlusconi denied the accusation, but there are signs of trouble ahead for the Italy’s longest-serving prime minister: Prosecutors are examining images that Patrizia D’Addario allegedly took of his bedroom and telephone recordings of him allegedly sweet-talking her, and the Catholic Church is warning that the “limits of decency” have been breached.

A defiant Berlusconi said he has nothing to be sorry about.

“There is nothing in my private life that I should apologize for,” Berlusconi told the gossip magazine Chi, which he owns.

“I have never paid a woman. I never understood what the satisfaction is when you are missing the pleasure of conquest,” the 72-year-old premier was quoted as saying.

Until the interview, Berlusconi had simply dismissed as “garbage” and a smear campaign reports that an acquaintance had recruited three women, and paid two of them, to attend parties at his residences.

To break the silence and address the accusations directly, the premier chose the popular magazine that is part of his Mondadori publishing house.

On the cover, above a headline reading: “Now I do the talking,” a smiling Berlusconi sits on a lawn, his 1-year-old grandson at his side. In other photos inside, the premier is seen surrounded by his grandchildren.

The photos offer a stark contrast with the image of Berlusconi depicted in recent weeks by Italian newspapers: a rich and powerful flirt who liked being surrounded by pretty women while he boasted of his visits to the White House, cracked jokes and sang songs.

“There must be limits,” said Famiglia Cristiana, a Catholic magazine that is distributed in parishes across Italy. “Those limits of decency have been exceeded.”

The scandal began weeks ago when the premier’s wife, Veronica Lario, announced she was divorcing him. She voiced outrage at his selection of starlets and showgirls for European Parliament elections and condemned his attendance at a birthday party for an 18-year-old girl, to whom he gave a gold and diamond necklace.

The woman at the center of the current scandal, D’Addario, told Corriere della Sera newspaper that she was paid $1,400 to attend a party last October at the premier’s residence in Rome, then returned Nov. 4 and stayed the night.

She told Corriere she wore a recording device during her time with Berlusconi — recordings that have been turned over to prosecutors. The prosecutors are investigating a businessman who is accused of recruiting and paying the women.