CCTV footage released by Greenpeace shows a number of men in balaclavas reportedly break into their offices in Murmansk, Russia.
The group said a mock cage, due to be used in a stunt as part of a campaign today, was taken from their premises.
Russian authorities are holding 30 activists and journalists following the capture of their boat during a stunt to highlight the environmental impact of Arctic drilling.
A court in Russia has charged the activists, and accompanying journalists, with piracy. They are currently imprisoned in jails in Murmansk, in the very north of Russia, and could face up to 15 years in jail.
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The victim, a man in his 40s, is being treated in hospital for "life-changing" injuries after the attack by two men who remain on the run.
Heavy security presence as 64,000 fans gather at the Stade de France stadium for the Six Nations rugby match between France and Italy.
Today's rain will clear into the North Sea tonight, but winds will stay strong, with showers feeding in to the north and west.