Italian voters went to the polls on Sunday in the first round of local elections expected to result in a landmark victory for the populist opposition party of comedian Beppe Grillo, the Five Star Movement (M5S).
More than 13.3 million voters are being called to elect new mayors in 1,342 municipalities, including large cities like Milan, Turin and Naples. But the most important race is in Rome, where M5S candidate Virginia Raggi is the clear frontrunner.
Voting is taking place from 7 am to 11 pm (0500-2100 GMT), with preliminary results expected early Monday.
Turnout was still low by 7 pm, with 46 per cent having cast their votes, according to the Interior Ministry. In Milan, turnout was 42 per cent, while in Rome it was even lower at 39 per cent.
Opinion polls have predicted that Raggi should come out on top in Sunday's vote, but short of the 50-per-cent threshold required for a straight victory, forcing a run-off on June 19 with the second placed candidate.
In two weeks' time, the M5S candidate should win comfortably, surveys have said, indicating that her most likely rival was going to be Roberto Giachetti from Prime Minister Matteo Renzi's Democratic Party (PD).
Raggi, who would become Rome's first ever female mayor, led a campaign seeking to capitalize on widespread anger for broken public services and the corruption scandals that have recently plagued the Italian capital.
Run-off votes are also expected in the other big cities.
Defeats in Rome and in other high-profile municipalities would confirm that Renzi's government - battling with banking crises, a stagnant economy, surging migration and several scandals - is experiencing a midterm slump in popularity.
More importantly, a victory would galvanize the opposition ahead of another key vote in October: a referendum on constitutional reforms that could spell the end of Renzi's career, as he has pledged to quit politics if they are rejected by voters.