SEATTLE—Japanese whalers on Thursday were to ask a U.S. judge to freeze the bank accounts of the Sea Shepherd Conservation Society, arguing that the Washington state-based anti-whaling activist group finances terrorism.

The society has led attacks on whaling ships in Antarctic waters, and some of the clashes have been shown on the "Whale Wars" reality TV show on the Animal Planet channel.

In a federal lawsuit filed in Seattle on Dec. 8, Japan's Institute of Cetacean Research said Sea Shepherd activists show up at hunts in boats, ramming whaling ships, dragging ropes near rudders and propellers, and hurling smoke bombs and bottles of acid at crews.

"Plaintiffs are entitled to be free from attack by what are essentially self-proclaimed pirates with a base in the state of Washington," the institute said in court documents.

U.S. District Judge Richard A. Jones scheduled a hearing on the lawsuit for Thursday. Sea Shepherd lawyer Dan Harris said in a filing that the court doesn't have jurisdiction in the Southern Ocean.

Japan's whaling fleet kills up to 1,000 whales a year, an allowed exception under a ruling by the International Whaling Commission. Japan is permitted to hunt the animals as long as they are caught for research and not commercial purposes. Whale meat not used for study is sold as food in Japan, which critics say is the real reason for the hunts.

Activists launched or threw glass bottles containing paint or butyric acid in one attack last year, the captain of a whaling vessel said in an affidavit translated from Japanese.

"A crew member could be blinded in such an attack," said Tomoyuki Ogawa, captain of the Nisshin Maru. "These attacks also cause fear in the crew, thus interfering with the prompt and accurate carrying out of orders."

Sea Shepherd president Paul Watson said in documents that his activists have never injured any whalers. He accused the whalers of attacking activists with concussion grenades, long-range acoustical devices, bamboo spears, heavy nuts and bolts, water cannons and prop foulers.

Each hunting season runs from about December through February. Sea Shepherd has sent boats to the waters off Antarctica for the past several years in an attempt to thwart the hunt. The two sides have occasionally had violent clashes, including a skirmish in which a Sea Shepherd boat was sunk after its bow was sheared off in a collision with a whaling ship.

Sea Shepherd lawyers deny the activists endanger whalers. Harris said in the filing that most of the institute's claims in the lawsuit are invalid.

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