Iran currently has one operating uranium-enrichment plant, in the central town of Natanz, which has churned out about 3,300 pounds of low-enriched uranium -- enough to build a nuclear weapon if it is enriched to a higher level. Iran says it has no intention of doing so.

A second facility, under construction secretly for years at Fordo near the holy city of Qom, was revealed earlier this year.

On Sunday, a Cabinet meeting headed by President Mahmoud Ahmadinejad ordered the Atomic Energy Organization of Iran to begin building five uranium-enrichment plants at sites that have already been studied and to propose, within two months, five other locations for future construction.