In Tehran, inspectors from the International Atomic Energy Agency are expected to certify that day whether Iran is respecting its engagement to rein in its nuclear programme, which the Obama administration and US allies fear is directed at producing a bomb.

If the inspectors are satisfied the Iranians are keeping their word, European Union governments, with the White House's blessing, are poised to deliver with surprising swiftness on their end of the deal: a six-month suspension of some of the sanctions that are hobbling Iran's economy.

Foreign ministers of Britain, Germany, France and the rest of the EU member countries will be in Brussels on Monday for one of their periodic meetings.

EU officials said yesterday the plan is that within 30 minutes of receiving an email, phone call or other form of communication from IAEA inspectors or their bosses in Vienna, the foreign ministers will unanimously approve the necessary changes in European Union legislation, and transmit their decision to the trade bloc's offices in the neighboring country of Luxembourg.

Within an hour or hour and half, the new regulations should be posted in the EU's official journal, published in Luxembourg, and take effect, a European Union official said.

All this should happen between 10 am and noon Monday, "unless something goes wrong," the official said on condition of anonymity because he wasn't authorised to speak publicly about the matter.

Under the deal with Iran, brokered by EU foreign policy chief Catherine Ashton, Tehran will be able to progressively take possession of USD 3.6 billion it has been paid for oil sold to China, India, Japan, Turkey, Taiwan and South Korea. Those funds are blocked in those countries' banks because of US sanctions.

Once the sixth-month suspension takes effect, Iranian officials could jet to Japan or India and carry "bags of cash" back home, the EU official said. But if the money is cycled through European banks, he said, Iranian authorities have been told that if they use accounts in the Central Bank of Iran or other Iranian financial institutions that are suspected of helping underwrite terrorism or the Iranian nuclear programme, the transfers will be blocked.

The temporary lifting of selected sanctions will also allow European Union shipping companies to use their own tankers or charter third country-flagged vessels to transport Iranian crude oil to China, India, Japan, Turkey, Taiwan and South Korea.