TEHRAN: Iran is to host a high-level team from the U.N. nuclear watchdog Monday as part of efforts to defuse dire international tensions over its atomic activities through dialogue.

But other words being spoken in Israel, the United States and Britain – and Iran’s defiant moves to boost its nuclear activities – underlined the prospect of possible Israeli military action against the Islamic Republic.

Iran also signaled Sunday that it is ready to hit back hard at sanctions threatening its economy, by announcing it has halted its limited oil sales to France and Britain.

Iranian Foreign Minister Ali Akbar Salehi said his country was keen to quickly resume mooted talks with world powers, once a place and date were agreed.

The last talks collapsed in Istanbul in January 2011, but Iran has responded positively to an EU offer to look at reviving them.

“We are looking for a mechanism for a solution for the nuclear issue in a way that it is win-win for both sides,” Salehi said.

But he added that Iran remained prepared for a “worst-case scenario.”

Such a scenario – war – remained very much the subtext of a visit to Israel Sunday by U.S. National Security Advisor Tom Donilon.

Israel has been gripped by speculation in recent weeks that it is closer to mounting a pre-emptive strike on Iran’s nuclear program, though Tel Aviv has denied reaching such a decision.

The United States, while not ruling out its own possible military option against Iran, was publicly being seen holding back its main Middle East ally from taking such drastic action.

“I think it would be premature to exclusively decide that the time for a military option was upon us,” the chairman of the U.S. Joint Chiefs of Staff, Gen. Martin Dempsey, told CNN.

“The U.S. government is confident that the Israelis understand our concerns,” The Jerusalem Post newspaper quoted Dempsey as saying to CNN.

British Foreign Secretary William Hague warned on the BBC Sunday: “I don’t think the wise thing at this moment is for Israel to launch a military attack on Iran.

Israel’s calculations will take into account an announcement by Iranian President Mahmoud Ahmadinejad last Tuesday that his scientists are boosting uranium enrichment by adding 3,000 more centrifuges to a facility at Natanz.

Iran also appeared to be about to install thousands of new centrifuges in another, heavily fortified enrichment facility near the city of Qom, a diplomat accredited to the U.N. nuclear watchdog told the BBC.

Iran insists that the enrichment is part of a purely peaceful civilian nuclear program.

Western nations and Israel, though, fear it is part of a drive to develop the ability to make atomic weapons.

A November report by the U.N. nuclear watchdog, the International Atomic Energy Agency, strongly suggested Iran’s program included nuclear weapons research.

The IAEA delegation due in Tehran Monday is to hold two days of talks with Iranian officials on those suspicions.

A previous visit on the same issue at the end of January, though, yielded no breakthrough.

“I’m not optimistic that Iran will provide much more information because I think any honest answers to the IAEA’s questions would confirm that Iran had been involved in weapons-related development work and Iran wouldn’t want to admit that for fear of being penalized,” Mark Fitzpatrick of the London-based International Institute for Strategic Studies told AFP.

The West has ramped up its economic sanctions on the Islamic Republic in an effort to force the country to halt the enrichment.

“But so far they haven’t worked and we’ve been seeing a regime that breaks all the rules,” Israeli Prime Minister Benjamin Netanyahu said Thursday.

Iran Sunday added to its defiance in the face of the sanctions by declaring no more crude was being exported to France and Britain, in retaliation for an EU-wide ban on its oil that will come into full effect from July 1.

Meanwhile, the Islamic Republic and Israel have shown a willingness to tangle, at least covertly.

Bomb plots to kill Israeli diplomats in India, Georgia and Thailand emerged Feb. 13 and 14, using similar methods to those used in the murder of Iranian nuclear scientists attributed to Israeli agents in the past two years.

Iran denied any involvement in the plots against the Israeli diplomats – one of whom was gravely wounded when her car was targeted in New Delhi. Israel has neither confirmed nor denied being behind the Tehran hits.

Israel and Iran have also made preparations for open conflict.

The Jewish state in 2009 reportedly purchased 55 bunker-busting bombs made by the United States, and this year called off its biggest-ever joint military maneuvers with the United States that were meant to have taken place around now.

The Islamic state has been conducting several war games – the most recent, land-based ones announced Sunday in central Iran – and flaunting its ballistic and cruise missiles.

Additionally, two Iranian warships sailed through the Suez Canal over the weekend and were in the Mediterranean, within striking distance of Israel.