Critics say Walter Veltroni has failed to capitalise on the recession
Italy's centre-left opposition leader, Walter Veltroni, has resigned after his Democratic Party lost a key local election on the island of Sardinia.
The result consolidated the hold on power of Italian Prime Minister Silvio Berlusconi's centre-right alliance, after its candidate for governor won.
Mr Veltroni had been criticised for failing to make gains on the government despite the deepening recession.
He said he would give a press conference on Wednesday.
Mr Veltroni led the centre-left into the general election last April after Prime Minister Romano Prodi resigned, but lost to Mr Berlusconi and his allies. He has since failed to make up ground on his rival.
In Sardinia, Mr Berlusconi's candidate and son of his tax advisor, Ugo Cappellacci, ousted the centre-left governor, Renato Soru, the founder of the Tiscali internet company.
It put the prime minister's ally in charge of a region where he owns a luxury seaside mansion and spends lots of time.