In Belgium, police arrested close to 400 people at a demonstration outside NATO's headquarters in the capital Brussels on Saturday. The police intervened when the demonstrators tried to force their way into the organisations headquarters, in an attempt to symbolically seal it off. They demonstrators said they thought a military organisation armed with nuclear weapons constituted a threat to world peace.
Protests against the organisation also took place in the Netherlands. Dutch police arrested 35 people outside the air force base in Nieuw Milligen, in the east of the country. Some were detained for attempting to climb over the base's fence; others because they could not produce valid proof of their identity.
The demonstrations were prompted by the upcoming 60th anniversary of the founding of the North Atlantic Treaty Organization. It came into being on 4 April 1949. To mark its sixty-year existence, celebrations are being planned for the French city Strasbourg and the German town of Kehl.
Source: http://www.radionetherlands.nl/news/international/6225124/Belgian-police-arrest-NATO-demonstrators