Demolition crews began work today to tear down a building that housed anti-capitalist squatters whose eviction last week sparked three nights of riots on the streets of Copenhagen.

Workers wearing masks to conceal their faces for fear of reprisals moved on to the site of Youth House, a centre for far-Left activists that was once host to Lenin, this morning.

Hundreds of anarchists, who had travelled from across Europe in response to an international appeal to join the demonstration, clashed with police after they cleared the building on Thursday.

Protesters set cars alight and hurled petrol bombs and cobblestones at officers. Some 643 people were arrested, including 140 foreigners, from Sweden, Norway, Germany and the United States, police said.

Today, as dust from the demolition filled the air, protesters shouted obscenities at police, while others hugged each other and cried.

“They are breaking my heart. I cannot stand it,” said Birgitte, a 21-year-old, who refused to give her full name saying those who had lived in the squat only used one name.

The area around the building was cordoned off and police wearing full riot gear kept a growing number of anarchists away from the site.

Per Larsen, a Copenhagen police spokesman, said on Danish television TV2 News: “We hope they will show their frustration only vocally, but we are out there on the streets, taking no chances."

Six people were arrested in the area for refusing to obey police orders or trespassing, but no violence was reported.

Demolition was halted just before noon to investigate a possible asbestos problem, Danish media reported. However, the Danish Working Environment Authority visited the site and gave the green light for the work to continue.

Tension over Youth House has simmered since 2000, when the local authority sold the site to a Christian group. Since 1982, the four-storey building had been used as a youth centre, when it became a focal point for anti-capitalist activism.

Police evicted the squatters four days ago using a court order issued last year.

Ruth Evensen, leader of the small congregation that bought the property, said it was “a total wreck" and a possible fire hazard. “It would cost us a fortune to have it fixed,” she said, declining to reveal the congregation’s plans for the site.

The riots were Denmark’s worst since May 1993, when police fired shots into a crowd of rioters protesting the outcome of a European Union referendum. Ten protesters were wounded at the time.

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