Last month, the Japanese research foundation Institute of Cetacean Research and the Japanese firm Kyodo Senpaku Kaisha Ltd. secured a U.S. District Court injunction against Watson and his Sea Shepherd Conservation Society, according to the institute's website.

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Last week, after a series of particularly dangerous confrontations, the group claimed to have brought about a suspension of whaling - an assertion rejected by the Japanese fisheries ministry and also its Institute of Cetacean Research, which organises the hunt.

BBC: Politics at play in Sea Shepherd-Japan whaling wars

"As a United States citizen, I will respect and comply with the ruling of the United States 9th District Court and will not violate the temporary injunction granted to the Institute for Cetacean Research, " Watson said in a statement Tuesday.

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