Milan, Italy (CNN) -- The long-awaited trial of Italian Prime Minister Silvio Berlusconi on charges of sex with an underage prostitute and abuse of power to get her out of jail opened Wednesday.
It lasted about 10 minutes and was adjourned until May 31.
Berlusconi had sex 13 times with underage dancer Karima el Mahroug, nicknamed "Ruby the heart-stealer," prosecutors say in legal papers seen by CNN.
He later made phone calls to police after she was arrested on suspicion of theft, prosecutors allege.
Lawyers for el Mahroug and the three police officers involved in her arrest refused Wednesday to press for damages against the prime minister.
El Mahroug's lawyer, Paula Boccardi, told reporters after the brief hearing that demanding damages would be essentially admitting that her client was a prostitute, which she denies.
Berlusconi's lawyer said the fact that none of the alleged victims wanted damages indicated that no harm had been done.
A women's rights group, Arcidonna, separately filed a civil suit against Berlusconi, accusing him of demeaning women over a period of 25 years. Judges must now decide whether to allow that suit to go ahead alongside the criminal trial.
By coincidence, all three judges and the main prosecutor in the case are women.
Italy's flamboyant leader has laughed off the sex and abuse of power charges, calling them an attempt to smear him and Italy. Both he and el Mahroug deny they ever had sex.
The allegations about the number of times Berlusconi had sex with the young woman come in legal papers accusing three of Berlusconi's associates with aiding and abetting prostitution.
The three are accused of selecting up to 33 young women, including 17-year-old el Mahroug, to attend parties at Berlusconi's house, where the women would perform erotic dances before the prime minister chose one to spend the night with.
He rejected the allegations last month, according to a leading Italian newspaper.
"I'm 75, and even if I'm a bit mischievous, 33 girls in two months is too much even for someone who is 30," the daily La Repubblica quoted him as saying on March 16.
He is being tried separately from the other three.
The Milan prosecution papers, filed March 15, name regional lawmaker Nicole Minetti, Berlusconi employee Emilio Fede and talent scout Dario "Lele" Mora.
In a CNN interview in Februrary, Minetti denied ever procuring prostitutes for Berlusconi and said the media had misrepresented the parties at his villa.
A lawyer for Berlusconi has asked Rome prosecutors to investigate an alleged attempt to falsify el Mahroug's birth records, he said.
The alleged falsification appears to be an attempt to make her appear not to have been a minor when Berlusconi allegedly paid to have sex with her.
Rome prosecutors did not immediately respond to questions about the case.
The Italian daily Il Fatto Quotidiano reported last week that someone had tried to falsify the birth records.
Berlusconi's lawyer, Nicolo Ghedini, said in a statement that he asked Rome prosecutors to investigate the allegation that two Italian "emissaries" had visited a birth-registry official in Morocco, where el Mahroug was born, and offered bribes to make the young dancer seem older.
Her age is significant because it is illegal to have sex with a prostitute in Italy only if she is a minor.
Ghedini suggested in the statement that he requested the investigation to establish that Berlusconi had nothing to do with any attempt to change birth records.
"We are dealing with something that tries to surreptitiously damage gravely Prime Minister Berlusconi, who is completely estranged to any eventual illegal action," the prime minister's lawyer said in a statement.
Berlusconi has been tried on at least 17 charges since his first term as prime minister began in 1994, but none of the cases has resulted in lasting convictions. Several were overturned on appeal.
CNN's Diana Magnay contributed to this report.