Philippe Douste-Blazy, the French foreign minister, said: "The Iranians have given no indication at all that they are ready to engage seriously on the substance of our proposals.

"Iran has failed to take the steps needed to allow negotiations to begin.

"We have no choice but to return to the United Nations Security Council and take forward the process that was suspended two months ago."

The decision came after foreign ministers of France, Britain, Germany, the United States, China, and Russia met in Paris on Wednesday.

However, Frank-Walter Steinmeier, the German foreign minister, said there was still room for negotiations with Iran. 

Annan intervention

Earlier, Kofi Annan had urged Iran to give a signal that it considered a package of incentives aimed at defusing a nuclear standoff as constructive.

The UN secretary-general, said: "Iran has had the proposals for some time and I urge him [Mahmoud Ahmadinejad, Iran's president] to try and give any signal, any indication, that Iran does consider the proposals constructive, takes them seriously and that they can be used as a basis for negotiations, even if they are seeking further clarification."

The five permanent members of the Security Council agreed last month on measures aimed at convincing Iran to abandon large-scale uranium enrichment, which produces fuel for power plants or weapons.

They told Iran that they wanted a clear response before this weekend's Group of Eight industrialised nations summit in Russia.