Czerlonka (Pologne) (AFP) - Activists chained themselves to logging equipment in Poland's ancient Bialowieza forest on Thursday to stop authorities from felling trees in Europe's last primeval woodland.

Starting at dawn, several of the 30 activists present attached themselves to wood-cutting equipment to stop it from leaving a nearby car park.

Others from Greenpeace and fellow environmental group Dzika Polska (Wild Poland) also held up banners that read "Stop logging" and "Save Bialowieza Forest" in the eastern village of Czerlonka.

Police intervened a few hours in and forced activists to unblock one of the machines but they continued to surround the other one.

Hours later, officers equipped with climbing gear forced the last of the activists to step down from a platform suspended above the machine, marking the end of the protest.

The Bialowieza forest is a UNESCO World Heritage site that is home to unique plant and animal life, including some 800 European bison, the continent's largest mammal.

The giant woodland straddles the border with Belarus and includes one of the largest surviving parts of primeval forest that covered Europe ten thousand years ago.

The Polish government says it authorised the logging, which began in May last year, to contain damage caused by a spruce bark beetle infestation and to fight the risk of forest fires.

Scientists, ecologists and the European Union protested and activists have alleged the logging is a cover for the commercial cutting down of protected old-growth forests.

In late April, the EU's executive branch -- the European Commission -- sent Warsaw a "final warning" saying it could take legal action to halt the large-scale logging.

The EU is concerned it could cause irreparable damage to the biodiversity of the woodland, that belongs to the EU's Natura 2000 network of protected areas.

Greenpeace Polska said in a statement that Thursday's action intended to "buy time to collect evidence regarding actions that go against EU rules and the UNESCO agreement."