Russian President Dmitry Medvedev said on Sunday he was alarmed by US assertions that Iran may have enough fuel for two nuclear weapons and warned that if confirmed the Islamic Republic may face new measures.
Central Intelligence Agency Director Leon Panetta told ABC's "This Week" television program that the agency thinks Iran has enough low-enriched uranium now for two weapons, but that Tehran would have to further enrich the material first.
"As to this information - it needs to be checked," Medvedev told reporters in Toronto, where he was attending the Group of 20 summit of rich and emerging nations.
"In any case, such information is always alarming because today the international community does not recognize the Iranian nuclear program as transparent," Medvedev said.
Russian leaders rarely comment on CIA statements and Medvedev's sharp comments indicate the gulf that has grown between Moscow and Tehran over recent months.
The Kremlin and Tehran had a public row last month after Iranian President Mahmoud Ahmadinejad admonished the Kremlin for bowing to what he said was U.S. pressure to agree further sanctions.
Urged on by the Obama administration, the UN Security Council - which includes Russia - this month passed a resolution to impose new sanctions on Iran over its nuclear development.
"If it is shown that what the American special services say is true then it will of course make the situation more tense, and I do not exclude that this question would have to be looked at additionally," Medvedev said.
'Western concerns valid'
The United States, key European Union powers and Israel say Iran is trying to use its civilian nuclear program to hide an attempt to create an atomic bomb, an assertion Tehran denies.
Russia has repeatedly called on Iran to remove the doubts that the international community have and earlier this year one of Russia's top security officials said that Western concerns were valid.
The CIA said that for Iran to have enough nuclear material for bombs, it would have to enrich its low-enriched uranium.
"We would estimate that if they made that decision, it would probably take a year to get there, probably another year to develop the kind of weapons delivery system in order to make that viable," CIA chief Panetta said.