Japan on Monday insisted it had made no decision on whether to resume whaling in the Southern Ocean next year, after a militant environmental group said Tokyo intended to evade an international court ruling.
Environmental campaigners from the militant Sea Shepherd group said on Wednesday a Japanese whaling ship had "rammed" its vessels in a skirmish in the Southern Ocean.
Militant environmentalists Monday accused Japanese whalers of attempting to crash into their ship as they tried to prevent harpoonists from hauling a slaughtered whale on board.
The Sea Shepherd conservation group asked the US Supreme Court on Monday to lift an order forcing it to steer clear of Japan's whalers, who are seeking legal reprisals over harassment at sea.
Anti-whaling activists began their annual campaign against Japanese whalers Monday with the Sea Shepherd's flagship, the Steve Irwin, leaving its Melbourne dock to pursue the harpoonists.
Anti-whaling activists intercepted Japan's harpoon fleet far north of Antarctic waters on Sunday, they said, with the help of a military-style drone.
Japan will go ahead with its annual whale hunt in Antarctica while boosting security to guard against possible harassment by environmental protesters, the agriculture and fisheries minister said Tuesday.