"It is an idea, not a structured proposal, we don't see it as mature and it has serious problems," the secretary of the country's Supreme National Security Council, Ali Larijani, said on national television.

The Russian proposal sought to overcome the key sticking point in talks between Iran and the European Union over the program, which the United States believes is a cover for nuclear weapons ambitions.

Moscow has suggested allowing Iran to conduct uranium enrichment in Russia, giving the country access to the nuclear fuel cycle while guaranteeing its nuclear program is for peaceful purposes.

Iran has denied it is seeking to build a nuclear bomb and says it is seeking only to produce electricity.

However, Larijani did not completely reject the Russian proposal.

"The (Russian) plan could be complementary and supporting, there are technological benefits, we have to examine them. It is not rigid and there is room for maneuver," he said.

Russia enjoys close ties with Iran and is helping build the Bushehr nuclear power plant in southern Iran.

Iran last week agreed to study the offer, after long maintaining that it would only look at proposals that accepted its right to conduct uranium enrichment on its own soil.

The Russian offer has been seen as a possible compromise solution that would see Iran satisfying its EU negotiating partners while retaining a right to enrichment and staving off the threat of United Nations Security Council sanctions.

Larijani also expressed disappointment with recent talks with Britain, France and Germany, the parties leading the European negotiations.

"I had hoped the recent negotiations in Vienna to make more progress. I don't have a negative view, but we hope future steps be taken more seriously and carefully," he said.

The talks, held on December 21 in Vienna, are set to resume again on January 18.

Larijani warned the West, which has threatened to push for the Security Council to impose sanctions, against taking strong action.

"If they act harshly, our behaviour will change. We have prepared scenarios and they cannot checkmate us easily," he said.

All rights reserved. © 2005 Agence France-Presse. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by Agence France-Presse. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of Agence France-Presse.