Italy's centre-left Democratic Party (PD) took a drubbing in mayoral run-offs on Sunday, losing 12 out of 16 larger cities to the centre-right including historic strongholds such as the northwest port city of Genoa.
Of the cities which previously had PD-backed mayors, the PD only managed to make gains in the southern city of Lecce and the northeast city of Padua.
PD leader and former premier Matteo Renzi, who is eyeing a return to power, said on Facebook that Sunday's poll results were "patchy".
"In terms of the total numbers of mayors, the PD is ahead, although it could have gone better," he wrote on Monday.
"Some losses hurt, starting with Genoa and L'Aquila," he went on.
"But local elections and national elections are completely different things."
The PD was the overall victor in the local polls, winning 67 of councils in towns against 59 for the centre-right, and 8 for the anti-establishment Five-Star Movement, according to a YouTrend pie-chart graphic tweeted by Renzi on Monday.
The Five Star Movement- which surveys say is slightly more popular than the PD nationwide - achieved dire results in the first round of voting on June 11 and made the run-off in only one of the 25 largest cities.
In the northern city of Parma, its incumbent mayor was re-elected as an independent after he fell out with the Five-Star Movement, leadership and left the party.
In the Genoa run-off, a candidate backed by Silvio Berlusconi's Forza Italia and the anti-immigrant Northern League party won with 55.24 percent of votes - over 10 percent points more than the centre-left candidate.
Northern League party leader Matteo Salvini claimed the Genoa result proved that prime minister Paolo Gentiloni had lost the country's support and should go.
"Today Gentiloni should resign," Salvini said. "Italians want change."
Turnout in Sunday's run-offs was low at 46 percent, as the searing temperatures across much of Italy may have kept voters away from the ballot box.
Including first round results from 11 June, more than 9 million people - about a fifth of the electorate - were eligible to vote in more than 1,000 Italian towns and cities with populations of over 15,000 people.
The mayoral vote was seen as a litmus test ahead of national elections due by the end of May next year. However, the first-past-the-post system used in local elections and which favours coalitions, may not be the voting system for the general election, where proportional representation is currently used.
The local poll results were a boost for Forza Italia leader and ex-premier Silvio Berlusconi, but also for his main rival, Salvini, heightening a leadership battle between the two.
Their strong showing suggests if their parties unite under a single leader, they could win the general election, Forza Italy's chief whip in the Italian parliament's lower house claimed on Monday.
"If we are united, the centre will win, with Forza Italia at the helm," Brunetta wrote on Facebook.
Although the local poll results may not be a reliable predictor of the national election outcome, Genoa is the latest of a string of defeats in the PD's traditional bastions. Last year it lost Turin, Italy's fourth-largest city, and the capital Rome, both to the Five-Star Movement.
Growth has continued to be sluggish during four years of PD rule and the situation of Italy's fragile banking system, which is weighed down by almost 350 billion euros of bad loans, remains critical.
Three different PD premiers have also struggled to handle an influx of half a million boat migrants who have landed since 2014 amid an ongoing crisis in the Mediterranean - arrivals which many Italians do not welcome.
