A Milan judge has ordered three of Italian Prime Minister Silvio Berlusconi's aides to stand trial on charges they allegedly abetted prostitution.

The aides — Emilio Fede, Nicole Minetti and Lele Mora — allegedly hired a 17-year-old and other young women for erotic parties at Mr. Berlusconi's home. They are also accused of establishing contact with Moroccan-born Karima El Mahroug, known as Ruby, who was 17 when she was allegedly paid to have sex with Mr. Berlusconi on 13 occasions.

Prostitution is not a crime in Italy, but exploiting prostitutes or paying for sex with a minor is.

Fede, Minetti and Mora have all denied any wrongdoing. Their trial will begin on November 21.

Their trial has been separated from that of the 74-year-old Mr. Berlusconi, who is facing trial on charges of having sex with the underage prostitute. He also is charged with abuse of power for urging police to release El Mahroug after she was arrested for theft. The Prime Minister says he is innocent of the charges.

Also Monday, an Italian court denied a request by Mr. Berlusconi's lawyers to delay his “Ruby” trial until February.