Environmental organisation Greenpeace was told on Friday that its ship Arctic Sunrise, which operates under the Dutch flag, can leave the Russian port of Murmansk.

The ship was seized last September and the 30 members of its crew were arrested on piracy charges following a protest at a Russian drilling rig in Arctic waters.

The crew were released in December.

A Greenpeace spokesman told news broadcaster Nos that he did not know why the Russians had chosen this moment to announce the surprise news that the ship is free to sail.

It is unlikely the Arctic Sunrise will return to the Netherlands immediately. After eight months in port, Greenpeace says it will need a thorough check to assess any damage and ensure it is seaworthy.