New York's main contract, light sweet crude for delivery in December, gained 36 cents to $97.16 per barrel.

Brent North Sea crude for December delivery advanced 53 cents to $115.53.

Crude markets were lifted by Berlusconi's announcement late Tuesday that he would step down after reforms aimed at stabilising Italy's debt-mired economy was passed later in the month, Phillip Futures said in a report.

"News that Italy's Prime Minister Silvio Berlusconi is to resign following approval of a new budget deal sparked a rally," it stated.

Berlusconi made the announcement after appearing shocked at results of a parliamentary vote on Italy's 2010 public accounts which saw his coalition lose its majority.

The premier had long dismissed warnings from the European Union (EU) and critics at home about Rome's ailing finances, but with his third term winding up, he admitted it was time to "show the markets that we are serious."

Italy has been on the ropes since last week when the government agreed to special surveillance from the International Monetary Fund and the EU to ensure it was meeting crucial targets to cut its massive debt.

The first EU experts are set to begin work in Italy on Wednesday.