The US government offered to crack down on anti-whaling protestors in secret negotiations with Japan, new cables released by WikiLeaks reveal.
The proposals, which would have seen US authorities investigate and act against the protest group Sea Shepherd Conservation, were cooked up as part of a deal to persuade Japan to cut the total number of whales it hunts.
Four cables sent from the US embassy in Tokyo and released today by WikiLeaks, reveal that secret negotiations took place between America and Japan ahead of a key meeting of the International Whaling Commission last year.
In return for a reduction in the number of whales killed in the Antarctic, the US pledged to back a move that would see Japan given the legal right to hunt whales off its own coasts.
US negotiators also offered to enact legislation to "guarantee security in the seas" by moving to stop groups such as Sea Shepherd from physically disrupting Japan's whaling activities.
One cable reveals that on 2nd November 2009, Shuji Yamada, Japan's vice-minister for international affairs, asked US negotiator Monica Medina about an investigation into Sea Shepherd's tax affairs.
In a later cable, Japanese negotiators are said to have told US diplomats: "It would be easier for Japan to make progress in the IWC negotiations if the US were to take action against the Sea Shepherd."
Sea Shepherd, led by Greenpeace co-founder Captain Paul Watson, has caused political upset in Japan by successfully preventing the country's whaling fleet from killing its annual quota of whales for several years.
US efforts to reach a deal with Japan faltered at the IWC meeting in June 2010, after the proposal was rejected by a majority of members, led by Australia, the wwwEuropean Union, and Latin American countries.
WikiLeaks' campaign to out more than 250,000 items of secret US diplomatic correspondence, nicknamed 'Cablegate', began on 28th November.
The site's founder, Julian Assange, currently faces extradition from the UK to Sweden to answer allegations of rape and sexual assault, amid fears that American authorities will request his further extradition to face charges of espionage in the US.