(BRUSSELS) - Around 200 environmental activists used barriers and concrete blocks to seal off entrances to a main European Union building in Brussels early Monday to protest over-fishing in European waters.

Yellow banners marked: "Shut down until fish stocks recover" were posted by Greenpeace members near the seven principle entry points to the European Council building -- where EU ministers and leaders hold their regular meetings.

At the main entrance, the protestors used cement to build a wall around 20 metres (25 yards) long and two metres (six feet) high. Fish nets foiled those trying to enter at other points.

At around 0830 GMT, police began detaining some of the activists -- around 30 of whom were sitting on the ground with their hands bound behind their backs -- and pulled some of the barriers down.

EU fisheries and agriculture ministers had been set to meet at the building, in the European quarter of Brussels, until Wednesday, and officials said that at least some ministers had been able to get in.

The meeting is aimed in part, at setting fishing quotas for each of the EU's 27 member nations for 2008.

"This policy, which has been followed for a quarter of a century, is an absolute failure," said Greenpeace representative Francois Chartier.

"We've seen it with anchovies, cod and now blue fin tuna" -- three species being over-fished in EU waters," he said.

In a letter to the ministers, the environmental group demanded that all new fish quotas set be at least equal, but preferably inferior, to the limits recommended by scientists.

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