In overnight violence, hundreds of black-clad youths set fire to street barricades and cars and threw bottles, cobblestones and fire crackers at police who fired tear gas to disperse the crowd.

"At times it was pretty violent," police spokesman Flemming Steen Munch said. Three police officers sustained minor injuries; there were no reports of injured rioters early Tuesday.

Police said they had arrested 59 people, aged between 17 and 49, since the clashes started Monday when workers tore down a condemned building in Christiania, a partially self-governing district in Copenhagen known for its alternative lifestyle community. All those arrested were Danes.

Although the building was largely abandoned, many protesters saw the demolition as part of a government plan to re-establish control over the freewheeling enclave.

The clashes came two months after angry youths went on a rampage in downtown Copenhagen to protest against the eviction of squatters from a youth center in another part of the city. Hundreds were arrested and 25 people injured in the riots, the worst clashes in Copenhagen in more than a decade.