Japan declared on Monday that its whaling fleet has stopped the hunting after it was harassed for 10 days by environmental groups like Greenpeace and Sea Shepherd Conservation Society in the Southern Ocean Whale Sanctuary.

On Tuesday Greenpeace announced that it prevented Japan’s main whaling ship, Nisshin Maru, to refuel in the icy waters of Southern Ocean by putting an inflatable boat between the refueler and the vessel.

Esperanza, Greenpeace’s vessel, chased the ship for hundreds of miles until it was out of the hunting grounds, Forbes reports.

Without its main ship, the factory boat, the other five vessels had to abandon activities because they could not process the catch.

In the last week the Japanese fleet could not hunt because of the activists.

For several days, Greenpeace has been following the fleet, while Sea Shepherd sent two activists on a Japanese ship in order to stop it from whaling.

Greenpeace issued a statement on Tuesday saying: “Activists from the Greenpeace ship Esperanza today blocked the fleet's factory ship Nisshin Maru from being refueled in Antarctic waters by the Panamanian-registered vessel Oriental Bluebird,” Reuters informs. “The activists ... placed their inflatable boat between the factory ship and refueling vessel, preventing them from coming alongside to refuel,” said the statement.

This move comes after last week two activists from Sea Shepherd boarded the Yushin Maru 2 to deliver a letter in which it was mentioned that the whalers are breaking the international and Australian law by hunting whales.

The two Australian Benjamin Potts, 28, and Briton Giles Lane, 35, were held for two days at the board of the ship. They were freed after the intervention of Australia government.

During the stand-off, Japan accused the activists of terrorism because they’ve found bottles on the deck with acid, while Sea Shepherd’s captain Paul Watson accused the crew of the whaler of taking the pair hostage.

The Japanese fleet launched last year a plan to kill 1,000 whales in the name of science, but Australia along with other nations believe that this can be done through non-lethal methods and accuse Japan for commercial whaling.