Italian prosecutors want to put premier Silvio Berlusconi on trial over accusations he paid for sex with a 17-year-old girl and then used his influence to cover it up.
Prosecutor Edmondo Bruti Liberati said he would file the request with a Milan court on Wednesday.
Prosecutors allege Mr Berlusconi paid for sex with the 17-year-old Moroccan, who has since turned 18, and then used his influence to get her out of police custody when she was detained for suspected theft, fearing her relationship to him would be revealed.
Karima el Mahroug ultimately was released into the custody of a Berlusconi aide who also is under investigation.
Supporters have never denied Mr Berlusconi called Milan police, but said it was to avoid a diplomatic incident, believing the girl, also known as Ruby the Heartstealer, was the niece of Egyptian President Hosni Mubarak.
Mr Berlusconi, 74, has been dogged by scandals related to his relationships with young women and wild parties at his villa. He denies ever having paid for sex and accused the prosecutors of seeking to drive him from office. Ruby has said they never had sex, though she says he gave her nearly £6,000 on their first meeting and jewellery later.
Prosecutors have been considering a speedy trial for the abuse of power charge, which would skip the preliminary hearing phase if there is overwhelming evidence to support the charge. But it is also possible they would keep the two charges together.
Prosecutors have alleged in documents forwarded to parliament that "a significant number of young girls have prostituted themselves with Silvio Mr Berlusconi."
Parliament last week denied prosecutors request to search Mr Berlusconi's properties for evidence in the case, and challenged the prosecutors' jurisdiction.
The scandal has brought criticism from the Catholic Church, as well as protests from Italian women who want to make clear that not all Italian women are showgirls or prostitutes. A major anti-Berlusconi protest is scheduled for Sunday.