The UN Security Council is poised to order sanctions against Iran today, placing an embargo on sensitive nuclear exports in the international drive to prevent Tehran from building a nuclear bomb.
With the diplomatic pressure set to increase after months of negotiations, the US and Britain are moving extra warships and strike aircraft to the Persian Gulf.
Much of the military focus is on countering any attempts by the Iranians to block oil shipments by mining sea lanes in retaliation against a UN resolution which British diplomats hope will be adopted unanimously by the 15-nation security council.
The draft resolution provides for bans on the import and export of material and technology relating to uranium enrichment, reprocessing and heavy-water reactors, as well as ballistic missile systems. It also calls for a travel ban and freezes funds and financial assets owned or controlled by entities or people associated with sensitive areas of Iran's nuclear or missile programme. Eleven organisations and 12 individuals are named as targets of the measures.
The draft text, sponsored by Britain, France and Germany, was expected to be adopted after a final negotiating session last night. It has been negotiated for months with the US, Russia and China, and watered down by the sponsors in hopes of obtaining Russian and Chinese assent.
On Wednesday, the Europeans agreed to drop plans to make travel bans mandatory against Iranian officials and scientists involved in nuclear proliferation. They had earlier exempted equipment for a light-water reactor being built by the Russians at Bushehr from the proposal.
The draft resolution, a copy of which was obtained by The Independent, calls on Iran to halt "without further delay" uranium enrichment activities which triggered fears the Iranians intend to produce the fuel for a nuclear bomb. Iran says that its intentions are purely peaceful, however.
Iran's chief nuclear negotiator, Ali Larijani, yesterday warned that his country would not comply with United Nations demands and threatened to end co-operation with the International Atomic Energy Agency (IAEA), which monitors its nuclear programme.
"If they ratify the resolution, Iran will be in a new situation. In this situation Iran will review its co- operation with the agency [IAEA] and [review] other political, economic and cultural fields," Mr Larijani said.
In anticipation of Iranian retaliation, Britain is doubling its naval strength in the area by sending two minesweepers, HMS Blyth and HMS Ramsay, to join HMS Sutherland, a frigate, and the Royal Fleet Auxiliary vessel, HMS Bayleaf.
The two additional warships arrived at the massive US base at Manama Bay in Bahrain last Tuesday.
As well as patrols, the ships will carry out training exercises with the navies of states in the area, which are becoming increasingly apprehensive about Iran. Officials in Bahrain accused Tehran of trying to destabilise the kingdom during recent elections. Iran was also accused of giving arms training to Shia activists to carry out possible future attacks on Bahrain, where the royal family are Sunnis.
Vice-Admiral Patrick M Walsh, the commander of naval forces in the US military's central command, said: "Iranian tone and rhetoric creates an environment of intimidation and fear. We need to reassure our friends we have the capabilities to secure the critical sea lines of communication."
Iran's President, Mahmoud Ahmadinejad, suffered a setback this week in his first electoral test since being elected 18 months ago.
Yesterday's final results of local council elections confirmed that his moderate rivals won a majority of seats, and his allies won less than 20 per cent nationwide.
But the Iranian leader kept up his defiant rhetoric against the West yesterday. In comments mocking the US President, George Bush, he said: "Oh, the respectful gentleman, get out of the glassy palace and know that you are the most hated person in the eyes of the world's nations and you can't harm the Iranian nation."
The draft resolution
Invokes Chapter 7, Article 41 of the UN Charter, which makes enforcement mandatory - but excludes military action.
All nations must ban goods and technology that could contribute to Iran's programme, or to ballistic missiles. Applies to exports and imports.
Freezes funds and financial assets of entities or persons associated with Iran's nuclear or missile programmes, including Iran's Atomic Energy Organisation and its vice- president of research.
Equipment for light-water reactors is not included, nor is low-enriched uranium. Exempts an $800m light-water reactor Russia is building in Iran at Bushehr.
Sanctions can be ended if the IAEA determines Iran has suspended its enrichment work, including research and development, so negotiations can resume. The first IAEA report is due within 60 days after the resolution is adopted.