Dozens of people have been arrested in Denmark after violence erupted amid a police operation to evict squatters.
Police were anticipating that trouble might spread across the capital
Protesters threw cobblestones at police and set makeshift barricades on fire outside the Copenhagen building, which has become a cause celebre in Denmark.
Police in riot gear blocked the streets while an anti-terror squad dropped from helicopters onto the building's roof.
Squatters have occupied the building since 1982, but it was sold by the local council in 2000.
The buyers, a Christian group, have a court order to have the squatters evicted - but they have vowed not to leave.
The building has been used as a base for left-wing activists for more than two decades. They say the council had no right to sell the building while it was still in use.
A protest against the eviction plans in December turned violent, and more than 300 people were arrested.
Shop owners in the Noerrebro district began boarding up windows after the operation began at about 0700 (0600 GMT).
Anti-terror police gained access to the building from the air
Youths gathered behind protest lines, yelling at police and throwing missiles.
"We have arrested 30 people who were in the building and some 40 others in surrounding streets," police spokesman Flemming Steen Munch told the AFP news agency.
He said the operation had gone to plan but that police had called in reinforcements, fearing that clashes could spread.
"We are in control of the situation and we are prepared for fresh trouble," he said.