WASHINGTON  An attack on the U.S. 5th Fleet, exploding Saudi oil refineries, and a Hezbollah operation against a soft target in the Americas, Asia, or Europe. These are scenarios America's intelligence analysts are now poring over as Israel signals its preparedness to deal with Iran's race for the A-bomb.

Click Image to Enlarge GALI TIBBON/AFP/Getty Fuga jets from the Israeli Air Force fly over Tel Aviv during a the celebration of Israel's 60th Independence Day on May 8.

The disclosure Friday in the New York Times of Israel's aerial training mission earlier this month over the Greek Mediterranean prompted America's intelligence chiefs to task analysts with developing contingency plans  or what one called "nightmare scenarios"  if the Israelis were to send their F-15s and F-16s to Iran's known nuclear enrichment facilities. While the training exercise was known at the time to American intelligence, the fact that Israel and America chose to make the mission public escalated the already high tensions between Tehran and Jerusalem.

The head of the International Atomic Energy Agency, Mohamed ElBaradei, speaking on Al-Arabiya television over the weekend, said an Israeli attack on Iran's enrichment facilities would turn the Middle East into a "ball of fire." Interviews with current and former national security officials in America suggest that Washington and its allies in the Middle East are bracing for unconventional and conventional attacks from Iran in response to such an Israeli action.

Possible scenarios include:

A terrorist attack on the Saudi oil port of Ras Tanura, an export point for oil bound for Asia. Saudi and American officials have in the past disrupted Al Qaeda plots on the facility, such as an attack on the Abqaiq oil processing plant near Dammam, Saudi Arabia, that killed two guards.

A naval assault on the U.S. 5th Fleet in the Persian Gulf. Iran still has warships equipped with Russian-designed Shkval torpedoes that it could fire at American vessels. Another possible attack would be suicide boat sorties similar to the one that bombed the USS Cole.

The commencement of a new round in the war between Hezbollah and Israel, with Hezbollah firing its Shihab missiles into Haifa and possibly the northern suburbs of Tel Aviv.

Hezbollah or Iranian intelligence terrorist operations on soft targets, such as shopping malls and community centers, in third countries and possibly even America.

A renewed effort to stir an uprising in Iraq through Moqtada al-Sadr's Mahdi Army or the special groups controlled by Iran's Revolutionary Guard.

While Europe, America, and other allies increase economic and diplomatic pressure on Iran, Israel is privately making it clear that it seeks to prevent Iran from even testing a nuclear device, as North Korea did in 2006. Most Western intelligence agencies agree that Iran's enrichment tests at Natanz have increased the odds of Iran mastering the technology necessary to create a test explosion.

In February, the director of national intelligence, Admiral John Michael McConnell, told the House Permanent Select Committee on Intelligence that Iran could be between six and 12 months away from mastering the technology needed for a nuclear device but not a warhead or bomb. Later in that hearing, he conceded that weapons analysts differ on the matter, providing a range of dates for nuclear fuel cycle mastery between 2010 and 2015, and adding that America's knowledge of the matter was incomplete.

The former deputy commissioner for counterterrorism for the New York City Police Department, Michael Sheehan, said his office had prepared for an Iranian response in New York the last time "there was a lot of saber-rattling on this," in 2005. He outlines some of his thinking in his new book, "Crush the Cell: How to Defeat Terrorism Without Terrorizing Ourselves."

In an interview, Mr. Sheehan said: "We very much considered how would the Iranians potentially respond to an American or Israeli attack. My thinking then and now is that Iran, in my view, is very rational. They will react in a very carefully and considered way, and I believe they will react with some sort of direct action by Iranian intelligence services or through a surrogate like Hezbollah."

Mr. Sheehan, who also served as one of President Clinton's ambassadors for counterterrorism, said that both the FBI and the NYPD have expelled Iranian intelligence officials from New York. He said he would not disclose details of possible targets considered in 2005, and he stressed that the faction of Hezbollah that carries out attacks in foreign countries, such as Khobar Towers in Saudi Arabia or the Jewish Cultural Center in Buenos Aires, is controlled by Iranian intelligence and not the political party and militia in Lebanon known as Hezbollah.

Asked whether Iran would attack the U.S. 5th Fleet, Mr. Sheehan suggested that the Iranians would be beaten, noting that the Navy would be on the highest alert should Israel attack Iran. A former chief of the Iran-Hezbollah office at the FBI's counterterrorism division, Kenneth Piernick, yesterday said he would guess that the Iranians would attack targets in the Persian Gulf.

"It seems to me the Iranians would have a greater power thrust closer to their borders. Our folks in Iraq and the Gulf will have their hands full. The Strait of Hormuz would be a target. They have made their demonstrations there in the past," he said. He added: "I would imagine my former colleagues are looking at Hezbollah's capabilities, but I have been away from the bureau for too long to speak on that now."

Mr. Piernick left the FBI in 2002.

In the past, Admiral McConnell has testified that Hezbollah has operatives in America. The network from Hezbollah was first disclosed in a series of federal prosecutions against the group's illicit fund raising. In some cases, individuals who were primarily raising money for the organization were found to have trained with the organization at the Bekaa Valley in Lebanon.

A former senior counterterrorism official for both Presidents Clinton and Bush, Roger Cressey, said yesterday that it might not be in Hezbollah's interest to do Iran's retaliatory bidding. "As much as Iran is Hezbollah's state patron, it is unclear whether Hezbollah would take operations at the behest of Iran inside the United States," he said. "That is not necessarily in Hezbollah's state interest right now."

A more likely scenario, Mr. Cressey said, would involve Hezbollah operatives attempting to terrorize softer targets in South America, Europe, or East Asia.

"There are other targets they could hit," he said. "You can't discount those scenarios."