"At the end of the meeting...it was agreed by all parties present that no definitive choice could be made at this stage," France's Research Ministry said in a statement.

European sources close to the talks said voting was postponed until February after the United States, China, Japan, Russia, South Korea and the EU failed to agree on a location of the project, billed as the future of renewable energy.

The ITER aims to create the world's first sustained nuclear fusion reaction, lasting several minutes, in a bid to harness the source of the sun's power and tame it, in a cleaner process than today's nuclear fission.

Fabio Fabbi, spokesman for European Union Research Commissioner Philippe Busquin, said the bloc would continue to campaign for its site in Cadarache, near the Mediterranean port city of Marseille.

"We regret the fact that the international partners were unable to reach agreement in a first shot, because although the Japanese site is of high quality, we think Cadarache is better and deserves to be the location," Fabbi said.

The failure to reach an agreement comes as a further blow to France, after the United States barred it and other opponents of the U.S.-led war in Iraq from bidding on lucrative contracts to rebuild the country.

PARTICIPANTS SPLIT

The European sources said participants in the talks split into two blocs, with the United States and South Korea in favour of Rokkasho, a remote fishing village in northern Japan, and Russia and China backing Cadarache.

Regional French official Stephane Salord said he was confident the EU location would win out in the end, suggesting that voting rules could be changed to prevent another stalemate.

"I am confident. The positions of the European Union, China and Russia are very firm whereas those of South Korea and the United States are more fluctuating," he said.

The stakes are huge. Construction of the reactor alone will take 10 years and employ 2,000 workers, at an estimated cost of 4.7 billion euros.

Fusion involves sticking atoms together, unlike the splitting of an atom that is at the heart of nuclear fission, the process used in today's atomic power plants and weapons.

It frees energy when two hydrogen atoms are smashed together to form a heavier atom of helium, and does not create much nuclear waste or risk reactor meltdown as fission does.

Fusion power has been touted as a solution to the world's energy problem, as it is low in pollution and has a virtually limitless supply of fuel in the form of sea water.