Iran resumed small-scale enrichment of uranium at one of its main nuclear facilities last week, a top Iranian official confirmed on Tuesday.
"The order to resume uranium enrichment has been issued and, in accordance with that, the Iranian Atomic Energy Organization has restarted the process," Javad Vaeidi, deputy secretary of the Supreme National Council, told reporters.
The work is being done at the country's main enrichment plant in the central city of Natanz, about 220 kilometres southeast of Tehran.
The announcement came a day after European diplomats said Iran had resumed uranium enrichment.
- FROM FEB. 13, 2006: Iran resumes uranium enrichment: report
Iran had suspended the process for more than two years while negotiating with European nations.
Western countries fear Iran's nuclear program will produce enriched uranium for nuclear weapons, but Tehran maintains it wants the fuel for electricity.
Earlier this month, the IAEA reported Iran's nuclear activity to the UN Security Council, which has the power to impose sanctions.
Tehran reacted defiantly, vowing to resume enrichment if it was reported.
Also on Tuesday, Iran announced it would postpone negotiations with Moscow over a Russian proposal until next week.
The Russian plan to enrich Iranian uranium on Russian soil is designed to calm fears that nuclear material will be diverted into a weapons program.
Vaeidi said the talks would begin on Feb. 20 in Moscow.