Iran meets the P5+1 powers - the United States, China, Russia, Britain, France and Germany - in Baghdad today to seek a way out of their long-running dispute over Tehran's nuclear programme. Here is a summary of the main issues:
Iran and the bomb
Iran says its nuclear programme, which has expanded dramatically in recent years, is for peaceful purposes, to generate electricity and provide medical isotopes. The Supreme leader Ayatollah Ali Khamenei said in February that possession of a nuclear bomb "constitutes a major sin", reiterating a religious edict he made in 2005. Many in the international community suspect the programme however to be a front for a covert nuclear weapons drive, with the UN Security Council passing four rounds of sanctions on the Islamic republic.
Rights and duties
As a 1968 signatory of the nuclear non-proliferation treaty (NPT), Iran says it has the right to a peaceful nuclear programme. However the treaty also stipulates Iran has to submit to inspections by the UN nuclear watchdog, the International Atomic Energy Agency, to determine that no materials or sites are being used for other purposes. The IAEA says that a lack of Iranian cooperation means it is unable to guarantee that this is the case.
Uranium enrichment
The trickiest part of making a nuclear weapon is creating the fissile core, either uranium or plutonium. Iran has, for some time, been enriching uranium to 3-5 per cent purities needed for power generation. But in 2010, it began processing to 20 per cent, and since January it had done so at the Fordo site in a mountain near the holy city of Qom. This takes it significantly closer to weapons-grade of 90 per cent and reduces the "breakout" time needed to make a bomb if it decided to do so.
Military dimensions
An IAEA report released in November last year increased suspicions that at least until 2003, and possibly since, Iran has done research into how to make a nuclear bomb. The report, which cited intelligence from several countries as well as the IAEA's own data and Iranian information, has been rejected by Iran as based on forgeries. The IAEA also says Iran refused it access in two visits earlier this year to the Parchin military site where some of this work is alleged to have been carried out.
Fuel swap
One way of cooling tensions would be to revive earlier ideas whereby Iran would ship out its stockpiles of enriched uranium to a foreign country, thereby easing fears that it could be further enriched and used in a nuclear weapon. In return, Iran would be supplied with fuel pads for the Tehran Research Reactor, which makes medical isotopes.
Additional protocol
Another way of building confidence would be for Iran to implement the additional protocol of the NPT, something it briefly adhered to but then rejected in 2006. This would give the IAEA greater inspection rights and help soothe one of the biggest concerns, namely that the country has sites the IAEA does not know about.