Silvio Berlusconi, Italy's prime minister, and the young woman he has been accused of paying for sex when she was underage, have both denied the allegations.

Karima El Mahroug, a Moroccan teenager who has been nicknamed "Ruby the heart stealer", appeared on a TV station founded by Silvio Berlusconi to deny the claims.

She said Berlusconi paid her $9,500 when she went to a Valentine's dinner at his villa, but that "he didn't put a finger on me".

But as Al Jazeera's Tania Page reports, the 74-year-old Berlusconi said the allegations are politically motivated and that he did nothing to be ashamed of.

Sabina Bellosi, a journalist for Agenzia Giornalistica Italia, an Italian news agency in Rome, said the latest allegations mark "the most serious and potentially explosive scandal yet" for Berlusconi, but are not likely to affect his popular support.

"It is a moment of instability in Italy and impossible to forecast the outcome," she told Al Jazeera.

"The most important thing for him is to have a strong political majority in parliament at this moment, and he is trying to build it.

"I think he still has strong popular support in Italy. The last survey told us that he still has 52 per cent of Italians who would vote for him, and [with] such strong support, I think he will have no problem.

"He has survived many problems, many scandals. He won a confidence vote just last month."