The foreign ministers of Britain, France and Germany and EU foreign policy chief Javier Solana highlighted the growing seriousness of the confrontation in a joint letter to Iranian authorities, which was made public in Paris.

"Were Iran to resume currently suspended activities, our negotiations would be brought to an end, and we would have no option but to pursue other courses of action," they said in the text addressed to Iran's nuclear programme director, Supreme National Security Council Secretary Hassan Rowhani (photo, left).

The three countries said they were seeking a special session of the International Atomic Energy Agency's board of governors "in the next few days to discuss the way ahead."

Germany weighs in

German Chancellor Gerhard Schröder told Iran that the West would not be divided in its opposition to Tehran building an atomic bomb. Schröder said the Iranian government could not pit European countries against each other over the issue and urged Iran not to make any "unilateral arrangements" during its ongoing negotiations with Germany and its EU partners Britain and France.

He said in Berlin that the European Union was ready to offer major economic incentives if Tehran made significant efforts at resolving what he called a "difficult and highly sensitive" situation.

For their parts, the French and US governments said, after the IAEA meeting, the issue could be taken to the UN Security Council where sanctions could be imposed on Tehran as punishment.

"We therefore call upon Iran not to resume suspended activities or take other unilateral steps and to confirm without delay it full commitment to the Paris Agreement," the European ministers said in their letter.

French Foreign Minister Philippe Douste-Blazy told reporters after a cabinet meeting chaired by President Jacques Chirac that the Iranian decision might spark "a major international crisis."

November agreement

Under the Paris Agreement struck in November last year, Iran agreed to suspend its nuclear activities in exchange for trade and nuclear co-operation incentives from the European Union.

But Tehran on Monday told the IAEA it planned imminently to resume uranium ore conversion, the first step in the cycle to producing fuel for nuclear reactors.

"The decision to resume suspended activities at Isfahan would, if carried out, breach both the Paris Agreement and the IAEA Board of Governors' resolution of 29 November 2004," the EU letter said.

"It would also further heighten international concern about the real objective of Iran's nuclear program." Iran's main nuclear negotiator, Ali Agha Mohammadi (photo), said in Tehran that "for us, the question is closed."

He stressed however that "the resumption is in no way a hostile act towards the Europeans and we regard the Europeans as our partners. We do not want a confrontation with the Europeans. The path to negotiations remains open."

Bomb plans?

The United States fears Iran intends to use its nuclear program to build the atomic bomb despite Tehran's insistence that it is pursuing only energy options.

US President George W. Bush has mildly endorsed the EU initiative to find a peaceful resolution, but also previously stated that "all options are on the table" to ensure Iran does not build a nuclear arsenal.

His spokesman, Scott McClellan, said of Iranian authorities: "If they're not going to abide by their agreement and obligations, then we would have to look to the Security Council."

French Prime Minister Dominique de Villepin also said Iran must comply with the Paris Agreement or face UN Security Council retribution.

"Iran must honour the commitments it has made. These commitments are commitments suspending all activity, conversion, treatment and enrichment of uranium," he told Europe 1 radio.

If Tehran refuses, "the international community will be forced to draw conclusions.... And the Security Council will be called on if Iran refuses to comply."