(CNN) -- Two anti-whaling activists who were seized by a Japanese whaling vessel two days ago have been handed over to Australian government officials on a ship in the Antarctic, Japan's Ministry of Foreign Affairs announced Thursday.



Australian citizen Benjamin Potts and British citizen Giles Lane, both members of the Sea Shepherd Conservation Society, jumped on board the Yushin Maru No. 2 Tuesday to deliver a letter saying the vessel was violating international law and Australian law by killing whales.



The anti-whaling group accused the crew of the Japanese vessel of kidnapping the men based on a video that showed Potts and Lane tied to the ship's railing. In the video, Japanese fishermen pace back and forth in front of them.



Australian Foreign Minister Stephen Smith Wednesday did not answer questions about whether the men would be charged for their actions, stressing instead that the immediate priority was to retrieve them.



"I'm not going to give a running commentary on who's done what to whom and the various allegations and counter allegation," he said.



Smith said the Japanese government -- which formally approached Australia to assist in the transfer -- did not lay out any conditions for the transfer, in which the men were brought on board the Australian ship, the Oceanic Viking.  Watch the anti-whaling activists board the Japanese vessel »



Capt. Paul Watson, founder of Sea Shepherd, had said earlier that the men were seized by the Japanese crew and assaulted.  Watch Watson describe the incident »



Sea Shepherd claims Japan's Institute for Cetacean Research, which is backing the operations, had said it would release the two activists if Sea Shepherd agrees to stop interfering in its whaling operations. The group says it will not agree to that demand.



The Japanese Fisheries Agency said Thursday it would readily hand over the two men.



But the agency charged that the Sea Shepherd members were the terrorists. At a news conference earlier, the agency released pictures of broken bottles they claim group members threw at the ship. They also released a photo of the two activists relaxing and drinking tea aboard the Yushin Maru.



"For some time, for 10, 15 minutes, I understand, they were tied to a GPS mast," Tomohiko Taniguchi of Japan's Foreign Ministry told CNN. "The Japanese crew members feared that two crew members from Sea Shepherd might do something violent."



He said Potts and Lane boarded the vessel without permission. Watson said the two boarded only after attempts to contact the ship by radio were unsuccessful.



Japan has been hunting whales in the Antarctic and apparently plans to kill as many as 1,000 this winter. The killings are allowed under international law because their main purpose is scientific.



"We regard them as poachers," Watson said. E-mail to a friend



CNN Correspondent Kyung Lah contributed to this report.
Who says that 2 of its members were kidnapped by the ship's crew? What reason did activists board the whaler for? Who was handed over to Australian officials? Who says ship's crew kidnapped 2 of its members? Who is Japan contacting? What whaling vessel was it? Who contacted Australia to help secure release? Who is contacting Australia to secure the activists' release? To which government were the anti-whaling activists handed over? Who was handed over? Who got kidnapped? Which government captured them?
Sea Shepherd Conservation Society, to deliver a letter saying the vessel was violating international law and Australian law by killing whales. Two anti-whaling group Australia Yushin Maru No. 2 the Japanese government Australian Foreign Minister Stephen Smith Australian Two Two Japanese
question: Who says that 2 of its members were kidnapped by the ship's crew?, answer: Sea Shepherd Conservation Society, | question: What reason did activists board the whaler for?, answer: to deliver a letter saying the vessel was violating international law and Australian law by killing whales. | question: Who was handed over to Australian officials?, answer: Two | question: Who says ship's crew kidnapped 2 of its members?, answer: anti-whaling group | question: Who is Japan contacting?, answer: Australia | question: What whaling vessel was it?, answer: Yushin Maru No. 2 | question: Who contacted Australia to help secure release?, answer: the Japanese government | question: Who is contacting Australia to secure the activists' release?, answer: Australian Foreign Minister Stephen Smith | question: To which government were the anti-whaling activists handed over?, answer: Australian | question: Who was handed over?, answer: Two | question: Who got kidnapped?, answer: Two | question: Which government captured them?, answer: Japanese