In Moscow, Russian Foreign Minister Sergei Lavrov told a news conference: “We are ready to meet at any location as soon as possible. We believe the essence of our talks is far more important (than the site), and we hope that common sense will prevail and we will stop behaving like little children.”

Ashton is overseeing diplomatic contacts on behalf of the powers hoping to persuade Tehran to stop higher-grade uranium enrichment and accept stricter U.N. inspections in return for civilian nuclear cooperation and relief from U.N. sanctions.

IRAN DENIES FORDOW BLAST

Reuters has been unable to verify reports since Friday of an explosion early last week at the underground Fordow bunker, near the holy Shi’ite Muslim city of Qom, that some Israeli and Western media said wrought heavy damage.

“The false news of an explosion at Fordow is Western propaganda ahead of nuclear negotiations to influence their process and outcome,” IRNA quoted deputy Iranian nuclear energy agency chief Saeed Shamseddin Bar Broudi as saying.

In late 2011 the plant at Fordow began producing uranium enriched to 20 percent fissile purity, well above the 3.5 percent level normally needed for nuclear power stations.

Western governments say the higher-grade enrichment marks a notable step towards weapons-grade uranium, even though it is below the 90 percent level suitable for nuclear bombs.

Iran says its enhanced enrichment is to make fuel for a Tehran research reactor that produces isotopes for medical care.

Diplomats in Vienna, where the U.N. nuclear watchdog agency is based, said on Monday they had no knowledge of any incident at Fordow but were looking into the reports. One Western diplomat said he did not believe them to be correct.