The Iranian chief nuclear negotiator, Ali Larijani, has dampened hopes that Tehran was leaning towards a compromise solution put forward by Russia in its nuclear dispute with the West.
Speaking to reporters on his return from a visit to China, Mr Larijani, who is Secretary of Iran's Supreme National Security Council, said the Russian plan to enrich uranium for Iran was not enough on its own to meet Tehran's energy needs.
The US President, George W Bush, yesterday threw his weight behind the Russian proposal, saying he thought it was a good plan and he would support it.
By producing enriched uranium for Iran under a joint venture in Russia, Moscow hopes to persuade Tehran it has no need to make its own enriched uranium.
Enriched uranium can be used in both nuclear power reactors and, when highly enriched, atomic bombs.
Iran says it only wants nuclear technology to generate electricity, not make weapons.
The governing board of the International Atomic Energy Agency is to meet next Thursday to discuss whether to refer Iran to the UN Security Council, where it could face sanctions.
