Around 300 anti-nuclear demonstrators have been arrested in Belgium, trying to break into a military site they claim is home to a battery of US atomic weapons.
A spokesman for the Belgian group Action for Peace claimed 800 protestors had tried to storm the Kleine Brogel base in the north of the country close to the border with the Netherlands.
Public prosecutors had already warned that anyone trying to gain illegal access to the installation would be prosecuted.
The presence of nuclear weaponry at Kleine Brogel has never been official confirmed.
But some experts believe the base could house B61 bombs that are also stockpiled in Germany, Italy, the Netherlands and Turkey.
The protestors hope to influence the outcome of a conference in New York next month to review the nuclear Non-Proliferation Treaty.
And in less than a week the US and Russian presidents are due to sign a new strategic nuclear arms deal that should lead to a significant reduction in the two countries nuclear arsenals.
The demonstration in Belgium was part of a series of anti-nuclear protests held across Europe.