BRUSSELS — Belgian police on Saturday detained hundreds of anti-nuclear activists protesting in and outside a military base where nuclear weapons are believed to be stored, rally organisers said.

A spokesman for the protestors said 300 people demonstrated near Kleine Brogel base not far from the Dutch border while more than 800 protesters tried to storm the police-protected military area.

Police put the total number of demonstrators at around 700.

“At this stage police has given the figure of 360 detained, registered and held in custody at aircraft hangars at the base,” said Benoit Calvi, spokesman for the Belgian non-government organisation Action for Peace.

Belga news agency quoted a police spokesman as saying that 270 people were detained.

Public prosecutors have warned that anyone trying to enter the base would be prosecuted.

Police officers arrested the demonstrators outside the base while those who breached the barbed wire enclosure were held by the military, said Calvi.

The Kleine Brogel demonstration was part of Europe-wide protests putting pressure on governments in NATO countries about to revise the alliance’s strategic concept.

The stockpiling of nuclear warheads at the northern Belgian base has never been officially confirmed but experts believe that they are part of the B61 nuclear bombs stockpiled in five NATO countries — Belgium, Germany, Italy, the Netherlands and Turkey.

Belgian Prime Minister Yves Leterme said in February his country wanted a world free of nuclear weapons and was promoting this position inside NATO.

US President Barack Obama’s administration has vowed to make “dramatic reductions” in its nuclear arsenal as part of a national review.