The police arrested at least 200 persons in the wake of anti-NATO demonstrations Thursday evening by a group of activists who had left a peaceful demonstration.
The activists tore down barriers and fences and fought their way to the square in front of the Oslo City Hall, where the delegates to the NATO summit were gathered.
The so-called Blitz activists had left a peaceful demonstration protesting against NATO's presence in Afghanistan.
The police used horses, dogs and finally teargass to stop the demonstrators who threw rocks, planks and bottles against the police.
During the night the police raided the so-called Blitz House in downtown Oslo, and confiscated large firecrackers and crates filled with rocks.
