Silvio Berlusconi's heterosexuality is the only reason he has been prosecuted in court, Russian president Vladimir Putin has claimed. If Italy's former prime minister were homosexual "no-one would have lifted a finger", Putin told members of the Valdai International Discussion Club.

"Berlusconi is on trial because he lives with women. If he was homosexual no one would have lifted a finger," he said.

Former centre-left Italy's prime minister and president of the European Commission Romano Prodi - Berlusconi's arch-enemy - was also at the meeting.

Putin's remark came after US Republican senator John McCain wrote a combative essay in the online newspaper Pravda criticising Putin. He described him as a dictator who ruled "by corruption, repression and violence".

"I am not anti-Russian," McCain wrote. "I am pro-Russian, more pro-Russian than the regime that misrules you today."

Berlusconi and Putin are bound by a decade-long friendship. The 76-year-old Italian media mogul invited the Russian leader to his private villa in Sardinia in 2008.

Putin has long defended Berlusconi and once dismissed concerns over the former prime minister's sex scandals by saying: "They mainly criticise him because they are jealous."

Berlusconi used a video message to the nation ahead of a Senate vote to oust him from parliament to relaunch his first political venture - Forza Italia (Go Italy!) - in a signal that he is ready to pull support from the government.

The video was aired a few hours before a Senate panel was due to meet to decide whether he should lose his seat in the upper chamber. A decision on whether or not to kick him out, based on a 2012 anti-corruption law stipulating that anyone convicted to more than two years in prison could not hold or run for office, has still not been made.

Senators agreed to call Berlusconi to speak for himself at a meeting in early October. Italy's top court upheld a four-year jail sentence for tax fraud against Berlusconi.