"We're moving offshore, to Texas, to the home of Exxon," Cindy Baxter of StopEsso told Reuters, adding that U.S. laws would guarantee them freedom of speech on the Internet.

Esso France had said the Greenpeace-backed group's use of a pair of dollar signs instead of the 's' letters in StopEsso could be associated with the Nazi 'SS', and that Esso customers could be directed to the group's website by mistake.

The court ruled earlier this month that the group could continue using the term StopEsso but had four days to remove the dollar signs from the logo or face a 5000 euros ($4,960) a day fine.

The group responded by plastering the logos on its French-language site with 'censored' signs. The site will now be run from Houston, Texas.

Exxon Mobil has come under fire from environmental groups for opposing the United Nations Kyoto Protocol on global climate change and for not investing in renewable energies such as wind and solar power.

They allege intense lobbying by powerful firms like Exxon contributed to the U.S. pulling out of the Kyoto deal last year.

The company denies it is unconcerned by global warming and says that it is tackling the issue on a number of other fronts, such as reducing energy use at the company's plants and working with the car industry to improve fuel efficiency in engines.

StopEsso has organised two rounds of protests at Esso fuel stations in the UK and in several European cities, in an effort to get motorists to buy their petrol elsewhere.