New protests against garbage mountains were held Friday in Naples and Italy's president also expressed alarm at the refuse piling up on streets in the southern city.
Protestors angered at the chronic waste problem torched four cars during the night and firemen put out dozens of other fires lit by residents irate at the rubbish outside their homes.
Militants of the rightist National Alliance party symbolically hanged 20 figures with signs calling for the resignation of Naples mayor Rosa Russo Iervolino. Other protesters are still picketing a major rubbish dump.
"I am not just concerned but also alarmed at the garbage situation in Naples," President Giorgio Napolitano, who comes from the city, told reporters.
The centre-left government has called for action to reduce the waste mountains, but also criticized residents who have been blocking traffic for three days to protest efforts to reopen a condemned dump in the western Naples suburb of Pianura.
Some 2,000 tonnes of garbage have been left on the streets of Naples and surrounding areas due to recurring problems at waste treatment centres.
Residents have stepped up protests all week, setting fire to the garbage.
On Thursday, the daily La Repubblica described the region, with a population of some six million, as "a community that is sinking and suffocating in its own excrement."
The problem has been compounded by closure of some plants because authorities say they have been taken over by the Camorra mafia -- who reportedly have made the waste business their second source of revenue, after drug trafficking.
The European Union opened an inquiry against Italy in June because of the piles of garbage in the Naples area which it said violated European refuse legislation.