Diplomatic representatives from France, Britain, Germany and Iran met here Thursday to discuss the Iranian nuclear program, the French Foreign Ministry said.

"The discussions are continuing with Iranian authorities toward obtaining all the guarantees relative to the peaceful nature of the Iranian nuclear program," ministry spokesman Herve Ladsous said.

The meeting with a high level Iranian envoy was part of a "continuation of earlier meetings" and was aimed at "establishing trust" with respect to Iran's nuclear program, Ladsous said.

The talks came following renewed allegations that Iran has restarted work on uranium enrichment, testing equipment and a gas that could be used to make nuclear warheads.

Iran agreed in October 2003 to suspend unilaterally and temporarily its uranium enrichment activities, after a visit by the French, German and British foreign ministers.

However, diplomats said Wednesday that Iran has broken the seal put by the International Atomic Energy Agency (IAEA) on the centrifuges at a nuclear installation about 250 km south to Teheran.

The equipment is used to produce enriched uranium, necessary to build atomic weapons. The seal breaking was considered as a sign that Teheran resumed its centrifuges building and assemblage.

Such revelations alarmed France, Germany and Britain. "This information derived from IAEA is very worrying," said German Foreign Minister Joschka Fischer on Wednesday.

The United States said Iran is trying to develop nuclear weapons, a charge Tehran denies, and urged the European "big three" on Wednesday to "hold firm" and make no deals with Iran.

"Iran had pledged to suspend the building and assemblage of its centrifuges. It broke its promise. It's worrying," said Adam Ereli, US State Department's spokesman.

US Secretary of State Colin Powell on Thursday reiterated the US view that Iran has not met its IAEA obligations or kept its commitments to the EU three.

"It is getting more and more likely that this matter is going to have to be referred to the Security Council," Powell told reporters accompanying him on a visit to Kuwait.

"Iran has made it clear they do not intend to abide by their commitments," he said, noting that "you just can't ignore it any longer."