Denmark has rejected a Japanese request to extradite anti-whaling activist Paul Watson over criminal charges dating back more than a decade, a Danish lawyer representing Watson said on Tuesday.

Watson, 74, a U.S. Canadian and founder of the Sea Shepherd conservationist group and of the Captain Paul Watson Foundation, has now been released from detention in the Greenland capital Nuuk, Greenland police said.

Watson was apprehended when his ship docked in the Danish autonomous territory in July.

"Paul is free !!!," Sea Shepherd France wrote on social media platform X.

Denmark's justice ministry, which is tasked with handling the extradition request, declined to comment immediately, but said it would issue a statement later on Tuesday.

Charges related to 2010 incident

Japan had issued an international warrant for Watson's arrest, seeking him on charges of breaking into a Japanese vessel in the Antarctic Ocean in 2010, obstructing its business and causing injury as well as property damage.

Watson denied the accusations against him. His lawyers have said Japan's justice system could not be trusted to give the activist a fair trial, and that Denmark should deny the request for extradition.

WATCH l Watson colleague worried about 'heavy-handed' approach from Denmark:

CBC News Network's Deana Sumanac-Johnson speaks with Captain Paul Watson Foundation's Locky MacLean

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Supporters of Watson had launched a campaign for his release, enlisting the support of politicians and celebrities, including French President Emmanuel Macron, Brigitte Bardot and Irish actor Pierce Brosnan.

France, where Watson has been residing since 2023, has also discussed Watson's case on a ministerial level, according to Denmark's Justice Ministry.

A spokesperson for Japan's embassy in Copenhagen declined to comment.

Watson left Sea Shepherd in 2022 to set up his own organization. He was also a leading member of Greenpeace before leaving in 1977 amid disagreements over tactics.