Several dozen environmental activists on Thursday occupied the Warsaw headquarters of Poland's state forest management agency to protest against logging in the Bialowieza forest, a protected UNESCO site that includes Europe's last primeval woodland.
Critics say Poland's rightwing government is defying a European Court of Justice injunction to suspend logging in the forest, but the environmental ministry says it is obeying the order and felling trees only for public safety reasons.
"We're calling for the withdrawal of heavy machinery from the Bialowieza forest. We demand an end to the logging," said Adam Bohdan, one of the activists chained to a security gate inside the building.
"All of our activity -- peaceful marches, petitions, blockades at the scene -- had no effect. Forest management continues to fell trees despite the decision of the European judiciary. And so we opted for this ultimate form of protest," he told AFP.
Forest management spokeswoman Anna Malinowska described the protest organised by the "Oboz dla Puszczy" environmental coalition as "illegal".
Police said they would remove protesters by force if they did not leave the premises, to which activist Joanna Pawluskiewicz responded: "We'll block the building's entryway right up till the end, till the police remove us."
Bialowieza includes one of the largest surviving parts of the primeval forest that covered the European plain 10 thousand years ago.
The vast woodland, which straddles the border with Belarus, is home to unique plant and animal life, including 800 European bison, the continent's largest mammal.
The Polish government began logging in May last year, saying it was clearing dead trees to contain damage caused by a spruce bark beetle infestation, as well as to fight the risk of forest fires and preserve road traffic.
Scientists, ecologists and the European Union protested and activists now allege that it is being used as a cover for commercial logging.