Iran agrees uranium deal with Russia

But the reported deal, announced yesterday, one week before the UN nuclear watchdog meets again in Vienna to decide whether to back Security Council action against Tehran, left many unanswered questions as to Iran's intentions. The chief Iranian negotiator said that more talks were needed.

A Foreign Office spokes-woman said there was "nothing to indicate" that Iran had addressed the key demands of the International Atomic Energy Agency (IAEA), and particularly its insistence that Iran returns to a freeze on all uranium-enrichment activities.

British and American diplomats have accused Iran of playing for time in the talks with Russia over a compromise deal in which uranium would be enriched outside Iran as part of a joint venture. Iran has also shown no signs that it intends to give up domestic enrichment of uranium, which can lead to the production of fuel for a nuclear bomb.

In comments unlikely to ease Western concerns, the Iranian nuclear chief, Gholamreza Aghazadeh, told reporters in the southern Iranian port of Bushehr that Iran would be setting an unspecified "precondition" to the deal.

An EU diplomat told Reuters that this precondition was almost certain to be Tehran insisting on its right to enrich its own uranium, in addition to enrichment in Russia, which would be unacceptable to the Europeans and the US.

Russia insists that its compromise offer of a joint venture is conditional on Iran agreeing to return to a moratorium on enrichment activities. Iran's decision to end a two-year voluntary freeze after last year's election of the hardline President Mahmoud Ahmadinejad, triggered an international crisis and has already led to Iran being reported to the UN Security Council by the IAEA governors' board.

The 35-nation board, which is due to meet again on 6 March, will decide whether to ask the council to take action. Konstantin Kosachev, head of the foreign relations committee in Russia's lower house of parliament, suggested Tehran was dragging out the negotiations and was unlikely to have clarified its position before the 6 March meeting.

Russia is helping Iran build a "safe" light-water nuclear reactor at Bushehr. Sergei Kiriyenko, head of Russia's atomic energy agency, Rosatom, stressed that Iran still had to take "serious steps" before the deal could be completed, apparently referring to a return to a uranium enrichment freeze.

Although the US President, George Bush, insists that all options remain on the table - including military - and unilateral action by Israel cannot be ruled out, European diplomats want to gradually ratchet up the pressure on Iran through the UN Security Council, which has the power to order sanctions if Tehran fails to comply with the IAEA demands.