Rome:
Italy's top court on Friday confirmed a prison sentence for former prime minister Silvio Berlusconi in his first ever definitive conviction, which could upset the country's fragile coalition government.
The court upheld a sentence for tax fraud of four years in prison of which three are covered by an amnesty, even though Berlusconi is certain to be granted community service or house arrest instead.
The Senate will have to vote to lift Berlusconi's immunity before the sentence can be implemented -- a process that could take weeks or even months.
A roar went up from a small group of anti-Berlusconi campaigners gathered outside the courtroom in central Rome as news of the ruling filtered through.
One elated activist uncorked a bottle of champagne and held up an image showing the scandal-tainted magnate behind bars reading: "This is how we want Berlusconi".
At a rally of Berlusconi supporters near his luxury residence in Rome, activists lowered their flags and stopped their chants of "Silvio, Silvio!"
The road in front of the palace, where Berlusconi huddled with close family members, lawyers and political allies, was blocked off by dozens of police officers after warnings of more protests.
Berlusconi was holding a conference of the leadership of his People of Freedom party in his residence to decide on what action to take, Italian media reported.
Berlusconi said earlier there should be no effect on the government even if he is convicted but diehard supporters are threatening to resign from parliament -- a move that could trigger fresh elections.
The government was installed this year following a two-month deadlock between Berlusconi's coalition and a leftist grouping led by the Democratic Party after February elections in which the two came neck-and-neck.
"Berlusconi is dead," said Beppe Grillo, leader of the anti-establishment Five Star Movement party.
"His conviction is like the fall of the Berlin Wall in 1989," the firebrand leader wrote in a blog.
Guglielmo Epifani, leader of the centre-left Democratic Party, said the sentence should be "respected, executed and implemented".
The court also sent back to the court of appeals another part of Berlusconi's sentence which would have condemned the 76-year-old three-time prime minister to a temporary ban from parliament.
