Naples, Italy ? The mayor of Naples appealed to residents Saturday to stay calm over the city’s garbage collection crisis, but scattered clashes between youths and police continued, news reports said.

Collectors stopped picking up trash Dec. 21 because there is no more room for it at dumps, and it has accumulated in stinking mountains in the city.

Mayor Rosa Russo Iervolino said she was appealing to the “overwhelming majority” of law-abiding citizens in the Pianura neighborhood, where work has begun to reopen a long-closed dump.

“Respect the law,” the mayor was quoted as saying by the Italian news agency ANSA.

Garbage pileups because of shortage of space in dumps have plagued the port city sporadically for several years. Although citizens are angered by the uncollected trash, they also have blocked plans to open new dumps in the Naples area.

Groups of youths with their faces largely covered threw stones and pieces of metal at police in several parts of the Pianura neighborhood before dashing away, some of them on motor scooters, the Italian news agency Apcom reported from Naples. Police were outfitted in riot gear, ANSA said.

Officials have blamed organized crime infiltration of garbage collection services and disorganized bureaucracy for the piles of trash, on the city’s outskirts and lining streets in Naples’ historic center.

Italian President Giorgio Napolitano has said he was alarmed by the situation and called on officials to take up their responsibilities in resolving the problem.

Residents have taken to burning the trash, unleashing clouds of smoke in the city.