Undersecretary of State John Bolton, the Bush administration's senior non-proliferation official, will urge Russia and other countries to lay the Iranian nuclear issue at the feet of the international community's premier body, US officials said.
US officials said it was unclear if Russia and European allies are ready join Washington in elevating the Iran nuclear issue to the Security Council.
"But we think the circumstances and the timing and the urgency of the matter are such that we are making a major effort," the US official said.
One official said Russia, under US pressure to halt cooperation on Iran's Bushehr nuclear power plant, has postponed delivery of critical reactor fuel until spring 2004.
He dismissed a report by the official Iranian news agency (IRNA) on Friday that Iran was ready to sign a protocol to return nuclear waste to Russia. Such a move could undercut US charges that Tehran is bent on producing nuclear weapons.
"The Iranians have been 'ready' to sign a spent-fuel take-back agreement for over a year," he said.
"We think the circumstances and the timing and the urgency of the matter are such that we are making a major effort"
Bolton, a leading neo-conservative will be in Moscow when the United Nations’ nuclear watchdog agency, the International Atomic Energy Agency (IAEA), is expected to issue its second report on Iran's nuclear activities.
His visit also coincides with the launch of six-party talks in Beijing on North Korea's nuclear programme.
While Bolton's Moscow discussions will include North Korea, Iran will be the main focus. The IAEA governing board plans to meet in Vienna on 8 September to consider its next steps on Iran.
Experts say Iran could be one to three years from having nuclear arms.
In its first report last June, the IAEA rapped Tehran for failing to comply with nuclear safeguards.
Since then UN inspectors have found enriched uranium in environmental samples taken in Iran. This could mean Tehran has enriched uranium without telling the IAEA, heightening suspicions of nuclear arms activity despite Iran's denials.