Iran says Moscow's compromise proposal on its nuclear programme is "off the agenda", after the Islamic Republic was reported to the UN Security Council.
The IAEA's ElBaradei cannot confirm Iran is not seeking weapons
A foreign ministry spokesman said "circumstances have changed".
Russia has sought to persuade Iran to move its enrichment programme to Russian territory, which would allow closer international monitoring.
On Wednesday, the UN nuclear watchdog referred Iran to the council, which has the power to impose sanctions.
"The Russian proposal is not on our agenda any more," foreign ministry spokesman Hamid Reza Asefi told reporters.
"Circumstances have changed. We have to wait and see how developments unfold within the five veto-holding countries [on the council]," he said.
He later issued a qualification, amid what correspondents describe as a series of conflicting signals from Tehran.
Mr Asefi said his country was still open to negotiations with Russia, as long as Iran's right to conduct nuclear fuel research on its own soil was recognised.
Iran has vowed to resist international pressure, insisting it has the right to civilian nuclear technology. It denies US and EU accusations that it is seeking to develop nuclear weapons.
The Russian proposal had been seen by many as a last chance for Iran to compromise with the UN nuclear watchdog, the International Atomic Energy Agency (IAEA).
The Iranian president has given no ground in negotiations
Last month, Iran agreed in principle on a joint venture with Russia to enrich uranium, but said further talks were needed.
Tehran then suggested a compromise deal, in which it would be allowed to enrich a small amount of uranium for research purposes, in return for accepting the Russian proposal. The US and Russia ruled out the idea.
Tehran's proposal came the week before an IAEA report on Iran's nuclear programme was forwarded to the UN Security Council for consideration of possible punitive action.
It is expected to discuss the issue as early as this week.
The council has the power to impose sanctions, but it is not clear that all its key members would back them.
Diplomats suggest the Security Council could start the process by putting out a statement calling for Iran to suspend its uranium enrichment activities and asking the IAEA to report on whether or not it complies.
The IAEA report said the Iranians had begun feeding uranium gas into centrifuges, a first step in a process that can produce fuel for nuclear reactors or bomb material.
IAEA head Mohamed ElBaradei said in the report that he was unable to confirm that Iran was not seeking nuclear weapons.