Russia has delivered the first shipment of nuclear fuel to Iran's Bushehr nuclear power station, the Russian state agency building the station said in a statement this morning.
Russia's Foreign Ministry said separately it had received additional written assurances from Iran that the fuel would not be used for any other purpose and urged Tehran to drop its own enrichment programme.
"The first stage (of delivering fuel) was completed on December 16th, 2007: containers with fuel which had previously been sealed by IAEA inspectors were delivered to the site and placed in special storage," plant constructor Atomstroiexport said.
Iranian officials could not immediately be reached for comment. Bushehr, which is nearing completion, will be Iran's first nuclear power station.
The delivery of fuel is likely to have far-reaching diplomatic repercussions because the United States and other countries, which suspect Iran of harbouring ambitions to acquire a nuclear weapon, have urged Moscow not to despatch the fuel.
Tehran says its nuclear programme is designed purely to generate electricity. Russia says Bushehr is being built in line with guidelines set by the United Nation's nuclear watchdog and there is no risk of Iran acquiring military technology.
Atomstroiexport's statement said delivering all the fuel for Bushehr would take a total of two months and would be done in several stages. Russian officials have previously said the Bushehr power station could start operating within six months of the fuel being delivered.
"The Iranian side has supplied additional written assurances regarding the fact that the fuel will be used exclusively for the atomic power station at Bushehr," the Russian foreign ministry said in a statement.
"We believe that qualitatively new conditions have been created which will allow Iran to take the steps which are demanded of it ... for the restoration of trust in the peaceful nature of the Iranian nuclear programme."
"This includes suspending work in the sphere of enriching uranium since, in the medium term, the Iranian side has no objective need for its own enrichment facilities - the Bushehr plant .. is supplied with Russian fuel for its entire lifetime."