As Iran continues to defy the United Nations Security Council by enriching uranium -- a process that could lead to building nuclear weapons -- the international community is looking at ways to prevent Tehran from continuing its enrichment program.  The Security Council might consider sanctions when it meets April 28. André de Nesnera looks at another possible move, a U.S. military strike against Iran.

Last week, the Iranian government announced that it has successfully enriched uranium at its Natanz nuclear facility.  Enriching uranium is a process that can be used either for civilian or military purposes.

Iranian officials have said for years their program is meant only for peaceful purposes, such as generating electricity.  But the United States and Europe believe Tehran's ambitions are ultimately to build a nuclear arsenal.

Iran's latest announcement came as the United Nations Security Council prepares to meet next week to decide what actions to take, if any, against Tehran.  Experts say the decision to enrich uranium is in clear defiance of the Security Council, which has called on Iran to suspend such activities.

The Iranian statements also coincide with a debate in Washington generated by recent news reports that the United States may be considering military attacks -- including possible nuclear strikes -- against Iranian facilities.

Senior U.S. administration officials have dismissed these reports and President Bush says diplomacy is the way to proceed.

"We want to solve this issue diplomatically and we're working hard to do so," Mr. Bush said.

At the same time, President Bush said "all options are on the table."  And at a recent White House briefing, spokesman Scott McClellan said President Bush is "skeptical" that the confrontation between the international community and Iran can be resolved peacefully.

Joseph Cirincione is a nuclear expert with the Council on Foreign Relations.  Citing Defense Department sources, Cirincione says some U.S. officials have already settled on the military option.

"Senior officials inside the administration have already decided that they want to hit Iran, that the whole point is to overthrow the regime in Iran," Cirincione said.  "The nuclear issue is just one of the issues for them, perhaps the issue they can use to justify the action.  But in their view, the object of the exercise is to continue the process of regime change that they believe they started with the war in Iraq.  I don't believe there is a consensus in the administration over this.  I think there is a debate over this.  What I don't see is any senior official strongly arguing for the negotiation path.  That's what worries me."

Cirincione says he hears the same rhetoric today as he did several years ago in the run-up to the U.S. invasion of Iraq.

"That's why it worries me when I see this coordinated campaign with the secretary of state, the secretary of defense, the vice-president, the president, the 'national security strategy' -- all coming out talking about the imminent threat from Iran:  that it's our central challenge, that it is the chief but state sponsor of terrorism, that we reinforce the notion of pre-emptive attacks, that we specifically keep targeting Iran as our major problem.  It is not our major problem," Cirincione said.  "Iraq is our major problem.  Iran isn't even our major nuclear problem.  That's North Korea.  They already have nuclear material."

A number of military analysts have written about a possible U.S. attack on Iran.  One of them is Paul Rogers from Bradford University in England [north-east of Manchester].  He says the military assault would come from the air.

"You would probably have anywhere between one and four days of raids," Rogers said. "The most intensive ones, coming at the start, would be the ones directed at the air defenses and the nuclear-related sites.  And it would be a combination, principally, of air strikes and the very considerable use of cruise missiles -- both [air-to-surface] standoff missiles launched from aircraft also sea-launched cruise missiles from cruisers, destroyers and submarines at sea.  One of the key components on the U.S. side would be the use of the B-2 stealth bomber, because that has an extraordinary capability to deliver precision-guided munitions with very little risk of any planes being shot down by the Iranian air defenses."

Rogers believes to cripple Iran's nuclear power program, the targets should not only be buildings or factories.

"There would be the need to try and kill as many as possible of the scientists, technicians, engineers, mathematicians who are involved in the process because, in some ways, one sets back a program much more by killing the personnel," Rogers said.

There is also a debate among military analysts whether or not the United States should consider using tactical nuclear weapons -- so-called 'bunker-busting bombs' - against Iran.  Some experts say that is one of the options considered by military planners.  But it doesn't automatically mean nuclear weapons will be used.

Ivan Oerlich, from the Federation of American Scientists, says nuclear weapons shouldn't even be considered in the planning process.

"The argument always is:  'Well, you want to give the president options in a crisis.'  But in fact, there are some options we don't give the president.  We don't give the president the option to use chemical weapons," Oerlich said. "We've decided that we are not going to have chemical weapons.  And we don't give the president the option to use biological weapons.  And I think that we ought to not include nuclear weapons, even if these plans are hypothetical, 'what if' kinds of planning exercises."

Analysts say the military option should be considered as a last resor, when all diplomatic efforts have failed.