The direct action anti-whaling group Sea Shepherd has released footage of dead whales aboard the Japanese ship the Nisshin Maru, claiming the ship was operating inside the Southern Ocean Whale Sanctuary near Antarctica.

According to Sea Shepherd’s website, three of the group’s ships are now pursuing the Japanese vessels hoping to drive them away from the sanctuary and disrupt their activity. The group claims footage shot from a Sea Shepherd helicopter shows three dead Minke Whales and one butchered whale they believe to be a Minke on the blood-soaked deck of the Nisshin Maru.

“Sea Shepherd will remain relentless in driving these fake, desperate and subverting ‘scientists’ back to Tokyo,” said Sid Chakravarty, a captain in the Sea Shepherd fleet.

Sea Shepherd Australia chairman Bob Brown claims the Nisshin Maru was first spotted from the air in Antarctica’s Ross Dependency and inside New Zealand’s territorial waters. New Zealand has called for an end to Japanese whaling programs in the past, but New Zealand Foreign Affairs Minister Murray McCully denied that any whaling was being done in New Zealand waters.

“…these are international waters and not within New Zealand’s maritime jurisdiction,” said McCully. He went on to call the practice of whaling in the oceans south of New Zealand “pointless and offensive to a great many New Zealanders.”

The accusations have also brought the Australian government under fire for failing to follow through on a promise to send aircraft to monitor whaling activity in the Southern Ocean.

Commercial whaling is prohibited in the Southern Ocean Whale Sanctuary under a designation by the International Whaling Commission (IWC), but a scientific research exception in the IWC designation allows Japanese ships to operate there. Japan, New Zealand, and Australia are all members of the IWC. Japan’s fisheries agency said its program is “in line with a research plan submitted to the IWC.”

The Sea Shepherd fleet has confronted the Nisshin Maru in the past, and was involved in a multi-ship collision with the Japanese vessel in February 2013. Both Sea Shepherd and the Japan’s fisheries agency accuse each other with responsibility for the incident. The Sea Shepherd operates in the Southern Ocean Whale Sanctuary as a part of their Operation Relentless campaign, now entering its 10th year.