Silvio Berlusconi in probe over teenage dancer Ruby

"Ruby" apparently attended parties held by Silvio Berlusconi

Italian Prime Minister Silvio Berlusconi is being investigated over his dealings with a teenage nightclub dancer, prosecutors say.

Mr Berlusconi is suspected of abusing his power by trying to have the Moroccan girl - known as Ruby - released from a police cell.

Some reports say the probe includes allegations of underage prostitution. The girl was 17 at the time.

Supporters of Mr Berlusconi, 74, say the claims are unfounded.

The prime minister has admitted calling the police on her behalf, but says he did nothing wrong.

His office has not yet commented on the prosecutors' latest move.

The dancer, who reportedly attended parties held by Mr Berlusconi last year, has denied suggestions that she had sex with him.

Prosecutors have not given details of the underage prostitution allegations.