Iran deployed warplanes and missiles Monday in an "exercise" to protect nuclear sites threatened by possible Israeli attacks and warned it could cut oil exports to more EU nations unless sanctions were lifted.

The European Union said it could cope with any halt in Iranian supplies.

Tehran's stance marked a hardening of its defiance in an international standoff over its nuclear programme -- and suggested it was readying for any eventual confrontation.

The moves came the same day as officials from the UN nuclear watchdog agency arrived in Tehran for a second round of talks they said were focused on "the possible military dimensions of Iran's nuclear programme."

Iran, while holding out hope of reviving collapsed negotiations with world powers, has underlined it will not give up its nuclear ambitions, which it insists are purely peaceful.

Much of the West and Israel, though, fear Iran's activities include research for atomic weapons.

The United States and Europe have ramped up economic sanctions against Iran's vital oil sector, while Israel has fuelled speculation it could be on the brink of carrying out air strikes on Iranian nuclear facilities.

Iran's military said on Monday that it has launched four days of manoeuvres in the south aimed at boosting anti-air defences to protect nuclear sites.

Missiles, anti-aircraft artillery, radars and warplanes were deployed in the exercise dubbed "Sarollah," a word borrowed from the Arabic meaning "God's vengeance."

At the same time, the deputy oil minister, who also runs the National Iranian Oil Company, warned that a cut in Iranian oil exports announced on Sunday against France and Britain could be expanded to other EU nations.

"Certainly if the hostile actions of some European countries continue, the export of oil to these countries will be cut," said Ahmad Qalebani, pointing the finger at Spain, Greece, Italy, Portugal, Germany and the Netherlands, Mehr news agency reported.

Iran exports about 20 percent of its crude -- some 600,000 barrels per day (bpd) -- to the European Union, mostly to Italy, Spain and Greece.

The EU reacted by saying it could cope.

"In terms of immediate security of stocks, the EU is well stocked with oil and petroleum products to face a potential disruption of supplies," said a spokesman for EU policy chief Catherine Ashton.

In Rome, French Foreign Minister Alain Juppe dismissed Tehran's move.

"Undoubtedly, Iran is very imaginative with regards to provocation. It is not Iran that decided to cut off its deliveries, we are the ones who decided to terminate our orders," he told reporters.

"It makes one smile," Juppe added.

Although the export halt for France and Britain was largely symbolic -- neither country imports much Iranian oil -- prices on world markets hit nine-month highs.

The Brent and New York contracts reached $121.15 and $105.44 a barrel in early trading -- the highest levels since May 5, 2011.

In late London deals, Brent North Sea crude for delivery in April stood at $120.14 a barrel, up 56 cents from Friday's close.

Iran's defiance included another pointed military deployment: two warships state television said had docked in Syria to help train its ally's sailors.

Israel said it "will closely follow the movement of the two ships to confirm that they do not approach the Israeli coast."

Iran has also flaunted "major" nuclear progress, declaring it was adding thousands more centrifuges to its uranium enrichment activities and producing what it said was 20-percent enriched nuclear fuel.

The UN nuclear watchdog, the International Atomic Energy Agency, in November issued a report voicing strong suspicions that Iran was researching an atomic weapon and missile warheads.

Last month it confirmed that a new, fortified uranium enrichment plant outside Iran's holy city of Qom had been activated.

The West has ratcheted up its sanctions to try to force Iran to stop enrichment, so far without success.

Meanwhile, the assassinations of three Iranian nuclear scientists and attempted bomb attacks against Israeli diplomats in several countries have pointed to a possible covert war between the two Middle East arch-foes.

But for all its flexing and posturing, Iran has also formally agreed to an EU overture to revive talks with world powers that collapsed a year ago.

However, the head of Iran's Atomic Energy Organisation, Fereydoon Abbasi Davani, told Al-Alam television that the powers -- the so-called P5+1 group consisting of the five permanent UN Security Council members plus Germany -- should ease the pressure.

"They would do better to change their method, because what they've used in the past hasn't met with success," he said.

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