Japanese whaling authorities say they are suing a group of environmental activists in the U.S. who have tried to disrupt Japan's controversial Antarctic whale hunt.

Kyodo Senpaku, which owns the ships used in the annual hunt, said Friday a lawsuit was filed against the Sea Shepherd Conservation Society in a U.S. court.

The anti-whaling activist group regularly sends small vessels to harass the Japanese fleet using stink bombs, dye markers and laser beams.

The Japanese authorities said in a statement that Sea Shepherd's “sabatoge activities” are “dangerous, life threatening and contrary to international law.”

The legal action comes after Japan angered environmental activists by annoucning that it will use nearly $30 million in earthquake and tsunami relief funding to boost security for the harvest.

Japan's whaling fleet left port this week.

The Japanese Coast Guard says it will deploy an unspecified number of vessels to protect the expedition.

Last month's harvest was cut short by one month because of interference by Sea Shepherd.

Commercial whaling was banned in 1986 by the International Whaling Commission, but Japan has continued the practice under an exception that allows whales to be killed for research purposes.

Whaling critics have scoffed at Japan's research claims, noting that whale meat harvested in the hunt is sold to the Japanese public.