Israeli Foreign Minister Avigdor Lieberman said Saturday a newly disclosed nuclear facility in Iran was proof the Islamic Republic was seeking nuclear weapons.

Many analysts believe the risk of a strike by Israel against Iran's nuclear program, even one not endorsed by its ally the United States, is significant.

Here's where matters stand:

COULD ISRAEL LAUNCH A STRIKE AGAINST IRAN?

It's a poker game with high stakes and a degree of bluff. Israeli leaders refuse to rule out any option. They do not believe Iran's assurances it wants only nuclear energy. Noting President Mahmoud Ahmadinejad's repeated assertions that Israel has no future, Israel has said an Iranian bomb would be a threat to its very existence that it simply would not tolerate.

Last year, however, it emerged officials were making plans for how Israel might live with a nuclear Iran in a state of mutual deterrence. And a June poll showed Israelis would not expect a nuclear Iran to attack.

Since becoming prime minister in March, Benjamin Netanyahu has, aides say, made ending threats from Iran a defining element of what he sees as his personal role in Jewish history. A 1981 Israeli air strike that destroyed Iraq's only nuclear reactor, as well as a strike in Syria in 2007 that is cloaked in mystery, set precedents. Despite official silence, few doubt Israel has nuclear missiles. Israeli Defense Minister Ehud Barak said recently: Israel can lay waste to Iran.

WHAT MIGHT HOLD ISRAEL BACK?

It is not clear how Israel would define achieving its goal of preventing Iran from acquiring nuclear weapons. But a pledge from Iran to forswear such arms, backed by some form of supervision and intelligence data, might be a minimum. Much will depend on Iran's actions and on U.S. President Barack Obama and others, who are pressing Iran through sanctions and diplomacy.

Obama demanded this week that Iran come clean about its nuclear program or risk sanctions that bite, after the disclosure of the new plant under construction south of Tehran.

While many analysts doubt Iran's denials of military intent, some say Iran may be content with showing it has the potential to go nuclear quickly, without actually arming itself. Israel, however, seems reluctant to accept that level of threat.

In the meantime, were Israel to consider a unilateral strike on Iran it would have to weigh several major risks:

-- of retaliation, not just from Iran but its allied guerrilla groups, Lebanon's Hezbollah and the Palestinian Hamas

-- of economic and diplomatic backlash from U.S. and allies

-- of a failed attack still triggering the above reactions

WHAT ARE THE KEY ELEMENTS IN TIMETABLE?

First, Iran's technology: Israel's national security adviser said in July it had passed a red line in terms of being able to make its own nuclear explosive but could not make significant amounts nor yet put viable nuclear warheads on its missiles.
Mossad chief Meir Dagan, seen as a key figure in Israel's Iran policy who has just had his mandate unusually extended to 2010, said in June Iran could have a viable warhead in 2014.

Second, diplomacy: Iran is to meet on October 1 with six major powers concerned about its nuclear plans. In May, Obama told Netanyahu that by the end of the year he expected to judge whether diplomacy was succeeding. This month, a former official said that if the West did not agree crippling sanctions by the end of the year, Israel would have to strike.

Russia, a veto-holding member of the Security Council and potential arms supplier to Iran, has a major role.

WOULD ISRAEL GO IT ALONE, WITHOUT U.S. BACKING?

Obama, at odds with Netanyahu over Jewish settlement in the West Bank and peace moves with the Palestinians, said in July he had absolutely not given Israel a green light to attack. He was responding to his vice-president saying that Israel had a right to act if it felt existentially threatened. Israel would be reluctant to anger its key ally. It would not wish Washington to be surprised, might even want U.S. help. But many analysts believe Israel might go it alone.

Some question whether Israel's U.S.-armed military has the range and firepower to destroy Iran's nuclear facilities without U.S. help. Analysts say Israel might be content with slowing any nuclear arms program, hoping for political change to end it.

Talk of an Israeli unilateral strike may also be part of a tactic of deterrence, or a bid to ensure U.S. cooperation.

HOW MIGHT ISRAEL ATTACK IRAN?

Overt or covert? Israel has been developing cyber-war capabilities that could disrupt Iranian industrial and military control systems. Few doubt that covert action, by Mossad agents on the ground, also features in tactics against Iran. An advantage of sabotage over an air strike may be deniability.

Militarily Israel can also deploy the following forces:

AIR -- 500 combat aircraft, including F-15s and F-16s able to bomb Iran's west, and further with aerial refueling, a technique for which the air force has been training. Planes can overfly hostile Arab states using stealth technology. Armed with bunker buster bombs that can be released with accuracy outside Iran's airspace. Israel is also assumed to have dozens of Jericho missiles designed to carry conventional or nuclear warheads to the Gulf. An Israeli nuclear strike is not likely. But, especially if war escalated, it could not be ruled out.

LAND -- Special forces could be deployed on the ground, to spot targets, and also possibly destroy them with sabotage.

SEA -- Israel sailed one of its three German-made Dolphin submarines into the Red Sea through Suez in June, opening a way to the Gulf. The submarines are believed to be capable of firing nuclear and conventional cruise missiles.

MISSILE DEFENSE - Israel is upgrading its Arrow missile interceptor, which is underwritten by Washington, and can also expect to avail itself of American Aegis anti-missile ships deployed in the Mediterranean. X-band, a U.S. radar stationed in Israel, further cements the alliance.

(Writing by Alastair Macdonald; Editing by Charles Dick)

(For blogs and links on Israeli politics and other Israeli and Palestinian news, go to blogs.reuters.com/axismundi)

Russia Iraq Nuclear weapons Israel