Protesters have set lorries ablaze and hurled stones and firecrackers at police, injuring 20 officers, as clashes flared over rubbish dump plans near Naples.
Police used tear gas overnight to disperse several hundred protesters near a waste treatment centre as the latest waste crisis grips Italy’s third-biggest city.
As tension resurged during the day, demonstrators smashed shop windows with clubs and torched at least five rubbish trucks in Terzigno and Boscoreale, two towns at the core of the protests.
As in the past, residents’ anger is directed against existing or proposed new dump sites because they fear contamination from unregulated and toxic waste disposal.
The protests have been going on for several days but escalated after officials confirmed a decision to open a new dump in the Vesuvio National Park.
As police escorted more than 30 rubbish trucks to a dump in Terzigno, protesters blocked the vehicles from unloading at an existing site and police charged and used tear gas to disperse them.
Some 20 officers and several protesters were hurt in the clashes, said a police spokesman.
Prime minister Silvio Berlusconi has called an emergency meeting in Rome on Friday.
It is the latest episode in a chronic scandal over rubbish collection in the southern region that has resurfaced in recent weeks, prompting calls for action from Mr Berlusconi’s government.
Political incompetence, corruption and the influence of organised crime have all contributed to a 16-year public emergency that has seen Naples’ streets regularly fill with rotting rubbish.
Two years ago, Italy’s prime minister intervened when collectors stopped picking up waste because dumps were full and residents protested against new ones.
Old dumps were reopened, some rubbish was shipped to Germany and the government also ordered the construction of new dump sites and incinerators.
The plans to open a new dump at the nearby national park have reignited the row, with rubbish trucks now forced to operate under police protection.