"Greenpeace warns that a nuclear power plant is an easy target for terrorist attacks," the environmental organisation said in a statement after its activists broke into the grounds of the facility in Borssele.

"Nuclear energy is never safe."

The group's activists, dressed as Romans, unfurled a banner saying "if the Romans had nuclear power plants we would still be guarding their nuclear waste."

The Dutch security services arrested 11 protesters.

In the coming weeks the Dutch government is set to decide on proposals to keep Borssele open until 2033.

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