The official said the government of Israeli Prime Minister Ehud Olmert plans to wait until France assumes the presidency of the European Union in July. France, he said, was expected to lead a European drive to expand sanctions on Teheran.

Over the last few weeks, the United States has raised the prospect of an Israeli air strike on Iran in 2008. Bush administration officials, particularly those from the Defense Department, said an Israel Air Force exercise in the Aegean Sea in June was meant to practice a massive air strike on Iran. The exercise, conducted with Greece, was said to have included more than 100 Israeli aircraft, including F-15s, F-16s and KC-130 air refueling tankers.

"The international community must not allow Iran to go nuclear," Israeli Defense Minister Ehud Barak said.

The U.S. intelligence community was said to have assessed that the Israeli air exercise concluded basic preparations for an attack on Iran. The intelligence community determined that the exercise demonstrated the feasibility of a massive Israeli air strike at a range of about 1,600 kilometers.

But the Israeli official said the air force exercise did not reflect plans to attack Iran. He said most of the exercise focused on search-and-rescue as well as mid-air refueling.

"There will not be any operation in 2008," the official said. "An operation such as this must be coordinated — at least with the United States."

Britain and France have become concerned over the prospect of an Israeli or U.S. strike on Iran. Britain has issued an alert to its embassy in Bahrain of an imminent U.S. confrontation with Teheran.

On June 30, U.S. Fifth Fleet commander Vice Adm. Kevin Cosgriff warned that Iran would not be allowed to block Gulf shipping. Cosgriff, responding to Iranian threats to halt traffic in the Strait of Hormuz, said this would constitute an "act of war."

"I cannot imagine, given the critical nature of that body of water, that the international community would not be outraged should Iran or any entity move to restrict the freedom of navigation," Cosgriff told a news conference at Fifth Fleet headquarters in Manama. "They are not going to be allowed to do so. It would be an act of war. In a tight oil market, the international community would respond vigorously to that."

On Tuesday, the U.S. television network, ABC News, reported that Israel could strike Iran's nuclear facilities in late 2008. ABC quoted a senior Pentagon official as reporting an "increasing likelihood" that Israel would attack Iran once it produced enough highly-enriched uranium to assemble a nuclear weapon.

"The Israelis are interested in such publications," Israel Television military analyst Yoav Limor said. "It tells the international community: 'Stop me.'"

A senior Israeli security source said the military was not ready to destroy Iran's nuclear weapons facilities. The source told the Israeli daily Maariv that the military, weakened by an inadequate budget, was incapable of a sustained strike.

"Years of neglect, and cancellation of projects and budgets, have left us without strategic ability for effective attack," the Israeli source was quoted as saying on Wednesday.

ABC quoted the Pentagon official as saying that Israel also wants to stage the operation before Iran acquires the SA-20, or S-400 air and missile defense system from Russia. The U.S. intelligence community has assessed that Iran could acquire the S-400 Triumf over the next few months.

"The red line is not when they get to that point, but before they get to that point," the official was quoted as saying. "We are in the window of vulnerability."