Iran moving closer to stage where it will be too late to destroy nuclear facilities, Israel warns

Reviving Western concerns that his government is still contemplating unilateral military action against Iran, Ehud Barak gave one of the clearest signs yet that Israel's support for new US and EU sanctions remains strictly limited.

"We are determined to prevent Iran from turning nuclear," he told the World Economic Forum in Davos. "And even the American president and opinion leaders have said that no option should be removed from the table.

"It seems to us to be urgent, because the Iranians are deliberately drifting into what we call an immunity zone where practically no surgical operation could block them."

Although Israeli intelligence and military officials have privately spoken of Iran's nuclear programme entering a "framework of immunity", it is the first time that a senior figure in Benjamin Netanyahu's government has done so in public.

Israel's fears that it might soon be too late to launch military action were bolstered earlier this month when Iran announced that it had begun to enrich uranium at its Fordow plant, which is buried so deep within a mountain it may be impossible for Israeli warplanes or missiles to destroy.

Mr Barak's ministry believes that once the bulk of uranium enrichment is carried out at Fordow, Iran will be in the immunity zone. Israel also reckons that Iran could be in a position to build a bomb within months, although US officials have been quoted as saying that Tehran will not be able to fit a nuclear warhead onto a missile for some years.

Mr Barak's warning came as inspectors from the International Atomic Energy Agency, the UN's nuclear watchdog, prepare to resume inspections of Iran's nuclear facilities.

Yukiya Amano, the organisation's head, urged Iran to show full co-operation after an IAEA report published last November concluded that Iran appeared to be pursuing the development of a nuclear weapon. Tehran has long insisted that its nuclear programme is peaceful in intent.

Iran has sent conflicting signals over its nuclear intentions. It has agreed to allow inspections and has spoken vaguely of its willingness to resume negotiations on the future of its nuclear programme.

But it has also threatened to seal off the world's most important oil waterway by blockading the Strait of Hormuz in the Persian Gulf.

In a demonstration of bravado, the Iranian parliament is to meet on Sunday to impose an immediate halt to all oil exports to the European Union.

The EU agreed this week to an embargo on importing oil from Iran, but said it would phase in the sanctions over six months.

If Iran carried out its threat it would pose serious challenges to Greece, Spain and Italy, the EU’s three most vulnerable economies, which account for more than 80 per cent of Iranian oil imports to Europe.

But such a measure would also harm Iran, which exports 18 per cent of its oil to the EU, as there is no guarantee that it would find alternative markets unless it was prepared to sell crude at a heavy discount.