June 23 (Bloomberg) -- The European Union stiffened its sanctions against Iran's nuclear program, shutting down the EU offices of Bank Melli Iran and denying travel visas to more Iranian officials.

The new EU sanctions were a year in the making and don't call into question an offer of economic incentives designed to persuade Iran to give up uranium enrichment, EU officials told reporters in Brussels today on condition of anonymity.

Iran has balked at three United Nations resolutions demanding a halt to uranium processing, ringing alarm bells over a possible war with Israel and stirring foreign-policy controversy in the U.S. presidential campaign.

A nuclear-armed Iran would be ``unacceptable,'' French President Nicolas Sarkozy told Israeli lawmakers in Jerusalem today. He threatened ``harsher and harsher sanctions'' and said Israel will not be ``left alone'' by the West.

The EU also extended a list of 15 Iranian organizations subject to an asset freeze and 20 senior nuclear officials barred from entering the 27-nation bloc. The names of the organizations and officials will be disclosed when the sanctions take effect tomorrow.

The European actions came after President George W. Bush pressed for further steps to isolate Iran, which western governments suspect of harboring a covert nuclear weapons program.

Iran insists its uranium enrichment work is peaceful and legal under the nuclear Non-Proliferation Treaty, with the goal of creating a commercial nuclear power industry.

EU Echoes UN

The EU sanctions don't go beyond what has been authorized by the Security Council, the officials said. The U.S. is pressing for penalties on Iran's oil and gas industry. Iran is the Middle East's second-biggest oil producer and is trying to develop exports of liquefied natural gas.

The EU announced the sanctions a week after foreign policy chief Javier Solana carried what he called a ``generous and comprehensive offer'' of economic and political incentives to Tehran to persuade Iran's leadership to stop enriching uranium, the key ingredient for weapons-making.

Solana acted as the emissary of the five veto-wielding members of the UN Security Council plus Germany. Iran has yet to publicly reply to the offer, while insisting that it will press ahead with a civilian nuclear program.

Bush is pushing for a fourth round of UN sanctions against the Islamic Republic, saying last week that a nuclear-armed Iran would be a threat to world peace. President Mahmoud Ahmadinejad has repeatedly called for the destruction of Israel.

Nuclear Program

Bush has given his backing to the economic and technological incentives to build up Iran's civilian nuclear program, while not ruling out a military response in case Iran refuses to comply.

Israel conducted military exercises on June 2 that the New York Times said were a possible rehearsal for an attack on an Iranian nuclear plant in Natanz as well as Iran's long-range conventional missiles.

The maneuvers involved about 100 aircraft and included mid- air refueling missions, according to two U.S. defense officials familiar with the Israeli operation who spoke on condition of anonymity.

Iran today dismissed the exercises as an empty gesture to divert attention from domestic problems. ``It is a hollow slogan,'' the state-run Islamic Republic News Agency cited Foreign Ministry spokesman Mohammad-Ali Hosseini as saying.

Israel is a ``long way'' from attacking Iran, Israeli newspaper Haaretz said yesterday, without citing anyone.

Israel's air force destroyed an Iraqi nuclear reactor in 1981, and last September demolished what the U.S. said was a nuclear reactor under construction in Syria. Israel and Syria are now undertaking indirect peace talks, mediated by Turkey.

Iran's anti-Israel rhetoric is coloring the U.S. presidential campaign, with Republican John McCain criticizing Democratic rival Barack Obama for being open to negotiations with Iran's leaders.

Obama on June 4 said he has an ``unshakeable commitment'' to Israel's security.

To contact the reporter on this story: James G. Neuger in Brussels at jneuger@bloomberg.net

Last Updated: June 23, 2008 08:30 EDT