"DEBACLE IN MOSCOW"

The diplomat said it was not clear if any senior aides to Heinonen would go to Iran as had been expected. A diplomat from another Western state also said he was informed Heinonen had canceled. IAEA officials refused to comment.

A diplomat familiar with IAEA dealings with Iran said the trip had been clouded by what he said was the hard line taken by Iranian negotiators who met EU officials in Moscow on Wednesday.

"It was a debacle in Moscow, and the Iranians are acting empowered," the diplomat said.

No consensus on sanctions emerged when the council's five permanent members -- Britain, China, France, Russia and the United States -- plus Germany held talks in Moscow this week.

Iran's deputy chief nuclear negotiator Javad Vaeedi met officials of Britain, France and Germany in Moscow after those talks, but there was no breakthrough, a British diplomat said.

Vaeedi arrived in Vienna late on Thursday, Iran's student news agency ISNA reported. There was no immediate confirmation.

Last week Iran defied U.N. and IAEA demands by announcing it had enriched uranium to the level needed in power stations and that it would push for industrial-scale fuel production.

Russia -- a veto-holder on the Security Council -- has long argued that sanctions might not persuade Iran to change course, but it has not before spelled out the level of evidence it would need to consider such measures.

President Bush, meeting Chinese President Hu Jintao in Washington on Thursday, did not appear to have persuaded him to allow tougher steps in the Security Council. Hu repeated Beijing's calls for a negotiated solution.

Russia rejected on Friday a U.S. call for it to scrap a planned missile sale to Iran, a day after rebuffing Washington's suggestion that it halt work on Iran's first atomic power plant.

"There are no circumstances which would get in the way of us carrying out our commitments in the field of military cooperation with Iran," Nikolai Spassky, deputy head of Russia's National Security Council, was quoted by Tass as saying.

"That includes ... our commitment to supply Tor systems to Iran," he said, referring to tactical surface-to-air missiles.

Bush has vowed to stop Iran getting nuclear weapons and has refused to rule out military options if diplomacy fails.

Worries about the nuclear standoff helped drive oil to record highs this week. Prices fell nearly $1 on Friday on profit-taking by fund investors, but held above $72 a barrel.