Iran's nuclear ambitions cause alarm in many countries. The US suspects Iran wants to build a nuclear bomb, has vowed to prevent this, and wants Tehran to halt all nuclear activities.
Iran says its nuclear regime is peaceful
Britain, France and Germany are trying to persuade Iran to scrap its uranium enrichment programme in exchange for technological and financial aid.
But Tehran insists that its intentions are strictly civilian.
We asked eight commentators for their views on the crisis.
What do you think about the issue? Please use the form at the bottom of the page to tell us your views.
Danielle Pletka, American Enterprise Institute
Radzhab Safarov, Centre for Iranian Research, Moscow
Dr Ali Ansari, University of St Andrews
Dr Ephraim Kam, Jaffe Centre for Strategic Studies, Tel Aviv
Professor Nasser Hadian, University of Tehran
Francois Heisbourg, Fondation Pour la Recherche Strategique
Sanam Vakil, Council on Foreign Relations, Washington
Dr Mehrdad Khonsari, Centre for Arab and Iranian studies
Danielle Pletka is vice president for foreign and defence policy studies at the American Enterprise Institute in Washington
The longer we wait and the more we negotiate, the longer Iran has to pursue a covert programme. The Europeans appear to be the only ones with an policy towards Iran. The US is not comfortable with EU policy, but, on the other hand, you can't beat something with nothing and so far, we've got nothing.
The road to co-operation between Europe and the US involves pursuing the "good cop, bad cop" routine because it will force the Iranians to be serious about dealing with the friendlier party. However, there's a suspicion in the US and in Europe, and a strong certainty in Iran, that when push comes to shove, the Europeans aren't going to be willing to cut the ties with the Iranians and say simply that Iran has been cheating, the deal is broken. We need to persuade the Europeans that even if you're the good cop, you have to be prepared to pull the gun and make the arrest.
There would be no benefit for the US or the Europeans if the administration became involved in the diplomacy because all of a sudden the US will become the carrot that the Europeans offer. Then, when we are unwilling to pursue the kind of incremental policy that has been a failure with North Korea, we are going to be the issue.
The Europeans and the Americans must agree that they are not going to allow the Iranians to exploit differences between them. We need to agree on some red lines and triggering mechanisms that would allow us to move to the Security Council.
Radzhab Safarov is the director of the Moscow-based Centre for Iranian Research and an advisor to the State Duma chairman
The Iranian nuclear programme has a completely peaceful nature, and there is no evidence to the contrary. The International Atomic Energy Agency (IAEA), the body responsible for the control over the spread of nuclear technology, has not yet presented any specific objections against it.
No other bodies, or governments, have the authority and sufficient expertise to assess this programme impartially. The IAEA checks the Iranian facilities on the weekly basis, but they have never found anything suspicious. I think the US's suspicions that Iran intends to develop nuclear weapons are not based on real facts, but on political attitudes.
Iran has suspended it nuclear activities in the past
If the US had a different kind of relationship with Iran, I am sure they would build dozens of nuclear power plants in this country. But since Iran is an independent and a rather stubborn state - from the US point of view - which does not succumb to the demands to suspend its nuclear programme, the US is exerting extreme pressure.
I don't think any country has a right to interfere with the Iranian nuclear programme, because it is a completely internal affair. As far as Russia is concerned, it is not worried about allegations that Iran might possess technology of dual nature.
If such concerns existed, it would have blocked this project and suspended co-operation with Iran in this field, because it would have been against its own interests. Russia and Iran have a common border in the Caspian Sea, so Iran's nuclear capability would threaten Russia's national interests, which are not confined to its own territory, but also lie in Central Asia and other former Soviet countries.
Dr Ali Ansari is a Middle East expert at the University of St Andrews
The best way to deal with the issue is through negotiations. But the negotiations should be real and offer things as well as demand them. The Europeans, the Americans and, as far as possible, the international community should offer coherent and realistic options that recognise the Iranians should be offered a way out with dignity.
The negotiations already going ahead are making incremental progress but they are being hindered by people on all side that don't want them to work. There are people on all sides - in Iran, in America, in Israel - who have a vested interest in the diplomacy collapsing.
I think there is a real possibility of strikes against Iranian installations - not because there is a deliberate strategy towards this goal but because the Americans and the Iranians are now subject to events and events can take on a momentum of their own. The rhetoric has ratcheted up the tension so much and neither side has a coherent policy towards the other.
The worry is that something like a border incident or an event in the Persian Gulf with American and Iranian ships clashing could escalate into something much bigger.
Iran has every right to follow a civil nuclear programme but there are various safeguards the Iranians could take to encourage trust. I don't think the Iranians are going down the weaponising route. I think they are fascinated by the technology and want to be able to say is they are scientifically advanced enough to be able to do it if they wanted to.
Dr Ephraim Kam is the deputy head of the Jaffe Centre for Strategic Studies at the University of Tel Aviv and author of the book From Terror to Nuclear Bomb - the significance of the Iranian threat
At the moment, I think the diplomatic option should be pursued. This means there is some chance, that Iran could eventually suspend its nuclear programme. It has already done this twice in the past year and a half.
At the same time, I do not think that the United States should give up, at least in principle, the possibility of a military solution. The Europeans should continue the diplomatic effort because Iran is not so willing to negotiate with the Americans. But it is clear that the European hand is strengthened by the military option.
Some Israeli leaders have stated in the past few years that Israel should consider military strikes if the political and diplomatic route fails. But, from Israel's point of view, I don't think this is the best scenario - it's a complicated operation and success is not guaranteed.
Professor Nasser Hadian is at the department of political science at the
University of Tehran
The majority of Iranian elite and government officials, fall into two categories: those who believe Iran needs nuclear energy and should acquire nuclear knowledge and technology, and those who argue that Iran should not only have nuclear technology as alternative sources of energy but also possess a nuclear weapons capability.
Only a small number argue that Iran should withdraw from the Non-Proliferation Treaty and develop weapons quickly. Most people argue that this would only increase Iran's vulnerability and does not enhance our security.
Presidents Putin and Khatami: Russia is helping Iran build its Bushehr nuclear reactor
A consensus between the two biggest groups has emerged along the lines that Iran should have control over the fuel cycle and not have full weapons capability. This would have some deterrent impact.
According to NPT, Iran is entitled to have the fuel generated inside Iran and officials are ready to give all sorts of assurances short of stopping the fuel cycle programme.
The US administration will eventually be forced to accept that - they have no reliable alternative. Total war is out of question and a surgical military strike would only enhance and strengthen the position of hardliners in Iran who argue for Iranians to go forth with full nuclear weaponisation while likely missing in the attack large chunks of Iran's dispersed nuclear infrastructure.
Francois Heisbourg is the director of the Fondation pour la Recherche Strategique in Paris
The American and European positions are about as distant as they could be. For the Americans, the specific threat of Iran's nuclear programme ranks second to the idea of regime change. For the Europeans, however, concern over Iran's nuclear ambitions is of the essence.
If the American position doesn't change, the negotiations between the Europeans and the Iranians are doomed to fail. The Iranians will resume the production of highly enriched uranium and eventually acquire a nuclear weapon.
Time is of the essence because presidential elections are scheduled in Iran for June. The nuclear issue is pretty much a consensus issue in Iran - it is one of the few things that makes the regime popular. Being hard line on nuclear affairs is an easy way for whoever is vying for power to acquire popularity.
Public opinion in the country is supportive of its government's atomic endeavours, it is linked to national pride and national sovereignty. Being seen as giving in during negotiations when nothing is being offered is highly unlikely.
The Europeans have nothing to offer: technology transfers, membership of the World Trade Organisation and access to international financial institutions cannot be provided by Europe. Support is needed from the US.
The US could go to the Security Council and ask for sanctions against Iran, but there have been American sanctions in place for the past 25 years. If they were to have any effect on the regime's ability to operate, this would have been discovered a long time ago.
Sanam Vakil is a Middle East expert at the Council on Foreign Affairs in the US
The US administration is walking a fine line right now. While it might want to go after Iran, its commitments in Iraq and Afghanistan mean that militarily, the US is overstretched. And, if it went to the Security Council now, both Russia and China would be reluctant to admonish Iran.
The US needs to sit down at the negotiating table with the Europeans.
The Iranians need some really big carrots to give up their nuclear programme. America could offer to remove sanctions but the Iranians would want more. Iran has US troops on its borders in both Iraq and Afghanistan and the ruling clerics feel they have a threatened ship of state. So diplomatic recognition or at least some sort of commitment from the US that it will not get involved with the internal affairs of Iran, would be a very big carrot, indeed.
I think George W Bush had told the Europeans that if they want to pursue the diplomatic option, they should give Iran the best possible deal and let the Iranians decide. Then if they don't get a deal, the US might feel it has the capital to take Iran to the Security Council.
Military strikes are being discussed in Washington but this would not be advisable as the US does not have the best intelligence right now with regards to Iran.
Iran has been very good at diversifying the facilities and locating them strategically near large population areas. The political cost of bombing these sites, while in the short run may forestall any progress for Iranians on the nuclear front, could, in the long run, be negative. First, the population could rally behind the ruling clerics, and second the loss of life would galvanise the Middle East and create a lot more opposition to the US within the region.
Dr Mehrdad Khonsari, is senior research consultant at the Centre for Arab and Iranian studies in London
The Europeans talk about a "grand bargain" with Iran but the Iranian regime is not willing to enter into a "grand bargain". The ruling clerics see their acquisition of nuclear weapons as an insurance against regime change.
They may agree to halt their programme, but the US might not halt its desire for regime change. The regime knows that if it can drag out the negotiations while, at the same time, reach a situation where it has crossed a nuclear line, then it cannot be touched.
Each side knows the positions they want to have and the options that are open to them, but the question is who can beat who to the count.
The majority of Iranians don't want a nuclear bomb and they despise the regime. The US is very popular among ordinary Iranians because of the stance it has taken against the clerics. Because of this, the US is concerned that when it comes to possibly exercising the military option, such as surgical strikes, it needs to find a way of doing it so as not to alienate the Iranian people.
That is the juggling act. Can the US conduct the military option in such as way as to not antagonise the Iranian population?
US claims that Iran is using its nuclear technology are completely baseless. I have been following this crisis, and the US has shown no proof of Iran building nuclear weapons, they just say they are!!
And let's face it, Iran needs nuclear power. Smog in Tehran is already bad enough. If they have nuclear power, they could sell more of their natural resources on the international market and rebuild the economy.
Brett Labach, Prince Albert, Canada
If the Middle East is to be free of nuclear weapons then ALL countries must be made to fully disclose and disarm.
For the country currently possessing the greatest arsenal of nuclear weapons and the only country to have used nuclear weapons against a civilian population, to demand that another country not develop nuclear weapons strikes me as at least incredibly hypocritical.
Bob Bergstrom, Seattle, USA
Who are the United States or the EU to say who can and can't develop nuclear technology? Why is Iran such a threat if it is developing nuclear weapons, but a number of EU countries and the USA already have them, but no-one talks about them being a threat? Let us not forget that only one nation has ever used atomic weapons in a war and they are the ones worrying about other people's arsenals. Perhaps Donald Rumsfeld, Condoleezza Rice and George Bush should be concerned with their own arsenal before passing judgement on the perceived arsenal of others?
P H, UK
Let's be honest here. First of all if Iran's intentions were not geared towards nuclear bomb capability, a compromise would have been reached long ago. That said, if both the US and Europe are opposed to Iran having nuclear capability, force will be required. Europe is careful not to jeopardise its reputation of high morals and therefore will not be the aggressor. The US on the other hand is already deep in the Iraqi mud and is not interested in damaging its already ailing reputation any further. My guess is that soon when negotiations fail, Israel will intervene as they did with the Iraqis in the past.
Benjamin Siegel, Amherst, MA, USA
Sad to say, but there appears to be no viable course of action that the West could take to induce and insure that Iran does not develop nuclear weapons. Some of the commentators have clearly stated why a military option is a non-starter. As for the carrot-and-stick approach, neither diplomacy nor sanctions has a ghost-of-a-chance of succeeding; Russia needs the income through military sales and China needs the oil. Thus, any UN action is also a non-starter because of the likely Security Council vetoes.
Mark Greenberg, Durham, NC USA
I've visited the Islamic Republic of Iran and their is too much smog in the capital Tehran. It seems very likely that the Iranian government is turning to nuclear power because the other sources have polluted Tehran and all of Iran. There are energy blackouts right and left throughout Iran every day. The Iranian economy is in a shambles. They want nuclear energy so that they can then sell all their gas and oil to other countries so that they can feed their poor people.
Jacob Cohen, New York City, USA
As an American, I don't have a problem with Iran having any number of peaceful nuclear technologies, including the ability to sell nuclear fuel on the international markets, which is something they recently expressed a desire to do some 15 years down the road. The problem for me comes from two things: Chants of "death to America" coming even from such places as the floor of their Parliament, and hiding their nuclear activity for all this time. Put two and two together and it's no wonder we're sceptical. For the best solution, the US has to get on board with the European diplomacy, but the Europeans have to really mean it when they say something and must be prepared to back it up, otherwise the Iranian government won't change because they know the Europeans will let them get away with it.
Wes, California, US
I do not see the Iran nuclear development as so much of a threat as our president does. However, I think from an ecological and probably economic point of view, there may be better ways for them to provide electricity, and that the US (if we're worried about power generation turning into nuclear power) should help them to turn to cleaner more safe means of generating electricity.
Dave, Groton, USA
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