The US secretary of state has urged China, Russia and India to back US threats of imposing sanctions against Iran over its nuclear programme.
Rice is trying to rally support against Iran's nuclear ambitions
Condoleezza Rice said Iran needed to get a "unified message" from the international community after reopening the Isfahan uranium conversion plant.
"We've all said that a next step to be expected would be referral to the [UN] Security Council," Ms Rice said.
Both China and Russia could use their veto power against a resolution.
In a reference to a recent report by the UN's atomic watchdog, Ms Rice said Iran was failing to honour its commitments towards the international community.
"I think that after the IAEA (International Atomic Energy Agency) report a couple of days ago, it is clear that Iran is not living up to its obligations, and so UN Security Council referral seems to be a reasonable option," she told a news conference in Washington.
Iran last month broke UN seals at the Isfahan plant, and resumed sensitive nuclear work it had suspended during negotiations with Britain, France and Germany.
The EU had offered Iran a package of economic and security incentives in return for the suspension of its nuclear activities.
But Iran insisted it had the right to pursue a civilian nuclear programme for peaceful purposes until negotiations broke down.
The US suspects Iran's scheme is a cover for a nuclear weapons programme.
Last week, an IAEA report said questions about Iran's nuclear programme remained unanswered, despite an intensive investigation.
Tehran argued the findings were politically motivated, but said it would continue to co-operate with the agency.