Russia questioned Tuesday an announcement by Iran that it was now making nuclear fuel on an industrial scale, a move that if confirmed would take Teheran closer to making an atomic bomb which the West fears is its aim.

Two UN inspectors, who could provide the first independent assessment of any Iranian progress, arrived Tuesday to inspect the Natanz uranium enrichment site where President Mahmoud Ahmadinejad said Iran had expanded its atomic work.

Iran's enrichment activity, until now at an experimental level, has drawn international criticism, including from Russia, its closest big power ally. The UN Security Council has slapped sanctions on Iran for not stopping the work.

"We are not aware of any technological breakthroughs in the Iranian nuclear program recently which would change the nature of work on enrichment being carried out in the country," Russia's Foreign Ministry said in a statement.

Russian Foreign Minister Sergei Lavrov said he was seeking clarification from the International Atomic Energy Agency and had no confirmation enrichment had begun in new machines.

Western analysts say Iran has made grand claims in the past about progress to strengthen its bargaining hand with the West but say Teheran has glossed over technical glitches that mean it is probably several years from being able to make a bomb.

Diplomats who follow Iran's nuclear file also suggested Iran's achievements could be more limited and aimed at showing Teheran would not be deterred from atomic work.

Iran, the world's fourth largest oil exporter, insists it wants only to make fuel for atomic power plants it is planning. Its first one is still under construction with Russian help.

An Iranian official said two IAEA inspectors had arrived in Iran for a week-long, routine visit to include Natanz. The result of their trip is likely to emerge only after they leave.

Inspectors from the Vienna-based IAEA routinely visit Natanz and other sites but Teheran halted more intrusive snap checks last year when its case was sent to the UN Security Council.

(China Daily via agencies April 11, 2007)