Standard & Poor's rating agency has downgraded 34 Italian banks.

The banks whose ratings were cut included the country's biggest bank Unicredit, which was downgraded from A to BBB+ with a negative outlook, the ANSA news agency said on Friday.

The action was a consequence of the downgrading of Italy to BBB+ decided Jan 13, Xinhua quoted a statement from S&P as saying.

On Jan 19, Milan Police carried out checks in a local S&P office as part of a probe against some rating agencies accused of manipulating market with 'false, unfounded or otherwise imprudent judgments' on Italy's economic-financial system and banks.