Denmark released anti-whaling activist Paul Watson from detention on Tuesday and said it had rejected a Japanese request to extradite him over criminal charges dating back more than a decade.
US-Canadian Watson, 74, founder of the Sea Shepherd activist group and the Captain Paul Watson Foundation, was released in Greenland's capital Nuuk, police in the autonomous Danish territory said.
Watson was apprehended when his ship docked in Greenland in July.
Denmark's justice ministry said it had based its decision on an overall assessment, including the age of the case and in particular an uncertainty over whether time spent in Greenland detention could be deducted from any final sentence in Japan.
"Based on correspondence with the Japanese authorities on this matter, the Ministry of Justice believes that it cannot be assumed with the necessary certainty that this will be the case," Justice Minister Peter Hummelgaard said in a statement.
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.
A spokesperson for Japan's embassy in Copenhagen declined to comment. Japan's foreign ministry did not immediately respond to a request for comment.
(Reporting by Tom Little, Louise Breusch Rasmussen, Isabelle Yr Carlsson and Jacob Gronholt-Pedersen in Copenhagen; Additional reporting by Kaori Kaneko in Tokyo; Editing by Terje Solsvik, Jan Harvey and Mark Porter)