Centre-left and protest parties have made gains in Italy's local elections, amid widespread discontent with the government's austerity drive.
The centre-right People of Freedom (PDL) party of former Prime Minister Silvio Berlusconi did particularly badly, with most votes counted.
The protest party of comedian Beppe Grillo, called Five Star, won nearly 20% in the northern city of Parma - enough to reach the run-off vote.
Technocrats are in power centrally.
The local elections in more than 900 towns and cities are the first major political test for Mario Monti's technocratic government, which took office in November.
At the weekend, national elections in France and Greece also produced big swings to the left.
Italy's main centre-left party, the Democratic Party, is part of Mr Monti's coalition and emerged strengthened by the local elections.
However the PDL, founded by Silvio Berlusconi but now run by one of his allies, was polling just 11.3% late on Monday.
One of the party's MPs, former Defence Minister Ignazio La Russa, said: "We made mistakes with the candidates we put forward".
"We're obsessed with finding people who look good, without knowing whether they have any experience, while people want reliable candidates," he said, quoted by the AFP news agency.
Comedian Beppe Grillo has used social networks extensively to campaign against Italy's eurozone membership. He is well known for attacking the political establishment.
He called the vote "an epic change", in a YouTube message.
"And this is just the beginning. The parties are melting into political diarrhoea. The citizens are taking back their institutions."
The BBC's Alan Johnston in Rome says Mr Grillo has rattled the established order and appears to have really made his presence felt in Italian politics.
In Palermo, Sicily, two centre-left candidates will go into a run-off for the mayoralty. A former mayor with a reputation for tackling the Mafia, Leoluca Orlando of the Italy of Values party, was leading with nearly 47%.
In the northern port city of Genoa, the centre-left scored nearly 49%.
The results are being watched closely because Italy is to hold national elections next year.
Polling took place over two days - Sunday and Monday - with about nine million Italians eligible to vote.
The right-wing Northern League, embroiled in a party-funding scandal involving its former leader Umberto Bossi, mostly scored poorly. But in Verona, the incumbent mayor, Flavio Tosi of the Northern League, was re-elected.