But some analysts familiar with the country's technology said Monday that President Mahmoud Ahmadinejad could be deliberately exaggerating Iran's capabilities, either to boost his own political support or to persuade the U.N. nuclear watchdog agency to back off.

The U.N. Security Council has demanded that Iran cease enrichment work, which the United States and some of its allies suspect is meant to produce weapons.

Russia's Foreign Ministry said Monday the Kremlin insists on a diplomatic solution to the standoff rather than any tough measures against Iran. And Russia's U.N. ambassador said that Moscow is hopeful that Iran will suspend uranium enrichment before an April 28 Security Council deadline, suggesting that the Islamic republic's tough line so far was a negotiating tactic.

Ahmadinejad, in a speech to students last week, claimed for the first time that Iran is testing a P-2 centrifuge for enriching uranium. Such a device would be a vast improvement over the P-1 centrifuges that Iran says it has used to do small-scale enrichment.

Iran previously told the International Atomic Energy Agency it gave up all work on P-2 centrifuges three years ago. It was not clear if Iran has been doing work all along on the updated model, or recently restarted efforts.

But Ahmadinejad's assertion is sure to raise concerns that Iran might have a more sophisticated atomic program than had been believed. The IAEA has long questioned whether Iran might have a parallel, secret nuclear program that is further along.