This comes as the United States said it would be “concerned” by Iran’s acquisition of any new nuclear technology, signalling opposition to a the European offer which would reportedly give Tehran a light-water reactor if it proves it is not secretly developing atomic weapons.

Iran insists it has the right to develop nuclear technology, but insists it can prove its ambitions are peaceful.

But the US claims it is a cover for acquiring atomic arms, and said if Europe was to transfer such technology. it would present problems given Iran’s past performance and its failure to comply with international demands to provide information on its nuclear program.

“We have long had concerns about Iran’s acquisition of nuclear capability, of nuclear technology, because for many years we have seen a confirmed pattern of non-compliance with safeguards,” said State Department spokesman Richard Boucher.

“We have seen the use of nuclear exchanges, nuclear technology, in order to develop what we can only describe as a nuclear weapons program and therefore we have been concerned and would remain concerned about Iran acquiring new capability in nuclear technology areas,” he said.

The offer by the so-called EU3 – Britain, France and Germany – reportedly will include a joint promise to provide Iran with some nuclear technology if it complies with demands from the International Atomic Energy Agency.

They are expected to demand Iran give up uranium enrichement in exchange for guarantees of imported nuclear fuel.

The country test-fired a long-range Shahab-3 missile on Wednesday, capable of hitting targets in Israel, in what is considered a deliberate show of military strength ahead of the negotiations at the IAEA headquarters in Vienna, which aims to give Iran a last chance to come clean before the agency’s governing board meets next month to decide whether Iran is in compliance or not.