Iran has stepped up its development of uranium enrichment facilities in recent years, and some analysts believe it could develop nuclear weapons within years if it decides to do so.
The US and Western countries have offered Iran a deal which would give it the right to develop nuclear energy for peaceful purposes on condition of a suspension of enrichment activities during any negotiations. The offer seeks to establish a situation in which Iran would not enrich uranium itself; fuel for its civilian nuclear power programme would instead be provided by another country, possibly Russia.
Iran insists that its programme is purely peaceful and that it has a right to develop nuclear technology.
The country's nuclear ambitions stretch back several decades. It received substantial assistance from Russia in the building its first nuclear power station, while Russia, China and North Korea are believed to have helped Iran build a series of short to medium-range missiles.