NAPLES, Italy (Reuters) - Italian police fired tear gas and water cannon on Wednesday during running battles with protesters demonstrating against Prime Minister Matteo Renzi during a visit to the southern city of Naples.

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Renzi, in Italy’s third-largest city to discuss plans for the urban development of a former industrial site, was greeted by a hostile group of 1,500 people, some of whom threw fireworks and stones and tried to force police road blocks.

The protesters, who oppose the redevelopment plans which they say have not involved the local community, brandished a giant-sized model of the prime minister in the form of Pinocchio and chanted “Renzi go home” in Neapolitan dialect.

Some foreign tourists were caught up in the clashes and four officers were slightly injured, according to local media.

The demonstrations took place at a difficult time for Renzi, whose industry minister resigned last week in a scandal over alleged influence-peddling related to the development of an oil field in southern Italian region of Basilicata.

The main opposition party, the anti-establishment 5-Star Movement, has presented a parliamentary motion of no-confidence in the whole government, which it says is in the thrall of industrial lobbies.

The motion, which will probably be voted on next week, has little chance of success, but it will keep the government under pressure ahead of mayoral elections to be held in Italy’s main cities later in the spring.

Renzi has repeatedly clashed with the mayor of Naples, Luigi de Magistris, a left-wing former magistrate who is running for re-election and is favored in the polls over Renzi’s candidate.

De Magistris, who has dubbed Naples a “Renzi-free zone”, said the premier had refused to involve him in the development of the Bagnoli former industrial site, which he claimed served the interests of construction groups rather than citizens.

He slammed Renzi’s visit as “an electoral catwalk.”

Renzi’s center-left Democratic Party remains Italy’s most popular party, according to opinion polls, although his personal approval ratings have fallen steadily over the last year.