A senior US official has called for continued international pressure on Iran to halt its nuclear programme.
Mr Bolton says Iran is determined to acquire nuclear weapons
UN Ambassador John Bolton said there was a sense of urgency given Tehran's defiance of the world community.
His remarks came after the UN nuclear agency, the IAEA, decided to send a report on Iran's nuclear activity to the UN Security Council.
Iran said it had done all it could to reach a peaceful settlement but the US had "hijacked" the diplomatic process.
Iran's ambassador to the IAEA (International Atomic Energy Agency), Ali Asghar Soltanieh, said: "We don't want confrontation but if this is the wish or policy of the Americans, then the Iranian nation will of course defend its integrity and national interests."
Russian Foreign Minister Sergei Lavrov said the agency should continue to lead efforts to resolve the dispute.
He expressed doubt that sanctions against Tehran would be effective.
"I don't think sanctions as a means to solve a crisis have ever achieved a goal in recent history," he told reporters.
Western nations have accused Iran of seeking to develop nuclear weapons, while Iran insists its nuclear programme is for civilian energy use only.
The Security Council is expected to discuss the issue as early as next 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 report being forwarded to the Security Council - which was leaked to the media last week - says the Iranians have begun feeding uranium gas into centrifuges, a first step in a process that can produce fuel for nuclear reactors or bomb material.
But IAEA head Mohamed ElBaradei, who wrote the report, was unable to confirm that Iran was not seeking nuclear weapons.
He has appealed to both Western and Iranian leaders to "lower the rhetoric".
"Everybody is looking forward to a political settlement... What we need now at this stage is a cool-headed approach," he said.
Iran declared in January it was resuming uranium enrichment for research purposes, ending a two-year suspension.