Larijani did not name the people involved, noting only they had visited the United States, but said such individuals had given the West the idea that Tehran would soften its position in the nuclear standoff.

"They (the West) have this bizarre idea that there will be changes allowing them to impose their will. The question is what creates such hopes? Sometimes one word sets back our work by six months," he said.

"But who are you? Are you speaking as nuclear officials?" he asked in a speech to members of Iran's elite Revolutionary Guards quoted by the Fars news agency.

"The Islamic republic is too powerful for three or four kids to affect its determination."

Iran has so far steadfastly refused to yield to the West's main condition for defusing the nuclear crisis -- that it suspends uranium enrichment, a process which makes nuclear reactor fuel but also atom bomb material.

The United States and Europe have refused to open full negotiations until Iran takes such a step and the UN Security Council has already passed two sets of sanctions to punish Tehran's defiance.

Larijani said the individuals tried to convince the West that the pressure would make Iran cave in and were thus encouraging further sanctions against the Islamic republic.

"Some of the actions of these people mean that the Westerners think that there are divisions inside the regime. And then they try and adopt resolutions.

"Certain people have gone to Washington and have encouraged the West to adopt resolutions and the West, on the basis of the signals received from inside, think that the situation will change in their favour".

At a time of acute sensitivity in the nuclear standoff, several prominent Iranians have in recent months been the target of legal proceedings over their contacts with the West.

Former nuclear negotiator Hossein Moussavian was detained in May on charges of harming national security by leaking sensitive information to an embassy in Tehran. He was later released on bail.

Three American-Iranians, including prominent Middle East scholar Haleh Esfandiari, are currently being held in jail accused of espionage and links to alleged US efforts to topple the clerical authorities.

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