Italian prosecutors are charging that Prime Minister Silvio Berlusconi had sex not once but 13 times with an underage Moroccan girl nicknamed "Ruby." Berlusconi paid for each encounter with the dancer, then 17, at his Milan villa during booze-fueled sex parties, according to court documents. The parties always began with dinner, followed by female guests performing erotic dances for Berlusconi, then sex with the partner of his choice, say prosecutors. The latest information emerged in documents filed against three men accused of procuring sex partners for Berlusconi, reports AP. The prime minister's trial for sex with a minor and abusing his influence begins next month. He has denied all charges.