Demolition crews on Monday started tearing down a disputed youth center that was at the heart of recent street riots in Copenhagen. Workers wore face masks under their helmets to conceal their identities as a wrecking ball slammed into the so-called Youth House, a graffiti-sprayed brick building in the Noerrebro district of the Danish capital. A police anti-terror squad on Thursday evicted squatters from the building, triggering three nights of clashes with leftist youth that turned parts of the city into a battle zone. More than 600 people were arrested and more than 20 were injured as protesters hurled cobblestones at riot police and set fire to cars and trash bins in Copenhagen's worst riots in 14 years. The Youth House for years served as a popular cultural center for anarchists, punk rockers and left-wing groups. The squatters considered it as free public housing, but courts ordered them out after the city sold the building to a Christian congregation. As dust from the demolition filled the air Monday, angry youth yelled obscenities at police who had cordoned off the area around the building. Others hugged and cried. "They are breaking my heart. I cannot stand it," said Birgitte, a black-clad 21-year-old woman with dreadlocks. She refused to give her last name, saying that was the norm among the people frequenting the building. About 30 police officers were keeping the youth away from the demolition site, while dozens more watched the situation from police vans. Those arrested in the street clashes included foreign activists from Sweden, Norway, Germany and the United States, police said. More than 200 were remanded in custody, while 15 were released. Others were still awaiting court hearings. The riots were Denmark's worst since May 18, 1993, when police fired into a crowd of rioters protesting the outcome of a European Union referendum. Ten of the protesters were wounded.