Anti-whaling campaigners Sea Shepherd attacked a Japanese whaling ship in the Antarctic Ocean by firing paint bombs at it and trying to jam its propeller with ropes, Japan's whaling body said Thursday.
Activists from the group's main ship, the Steve Irwin, on Wednesday approached the Yushin Maru No.3 on dinghies before also fired paint pellets, stink bombs and smoke flares, the Institute of Cetacean Research said.
The whalers responded with a water cannon, the institute said, describing what is becoming increasingly routine exchanges between whalers and activists on the high seas.
The institute, a quasi-public body that organises the country's whaling missions, said one of the Japanese crew was hit by a stink bomb but was not badly hurt.
The latest incident brings to nine the number of attacks Sea Shepherd has launched against Japanese whaling ships this year, none of which has caused major injuries to Japanese crew.
The institute has urged the Netherlands - where the Steve Irwin is registered - to take action against the campaigners. It has also issued similar calls to authorities in Australia and New Zealand, which Sea Shepherd uses to dock its ships.
Last month Japan and Australia were involved in a diplomatic incident when Tokyo tried three men from another campaign group, Forest Rescue Australia, for trespassing after they boarded a Japanese whaling boat.
Japan only agreed to hand the men over days later following intervention from Canberra.
Commercial whaling is banned under an international treaty but Japan has since 1987 used a loophole to carry out "lethal research" in the name of science.