Armed with fresh international backing for bringing Iran before the U.N. Security Council for its nuclear activities, the White House on Monday warned Tehran it has just one chance left to avoid referral for possible economic sanctions.

"The world is saying to Iran that it is time to come clean. The world has put Iran on notice," White House press secretary Scott McClellan said. "It is unacceptable the way Iran is behaving."

On Saturday, a majority on the 35-nation board of the U.N.'s nuclear watchdog agency approved a resolution that cited Iran for "a long history of concealment and deception" in a nuclear program Tehran insists is only for the peaceful production of nuclear power. The International Atomic Energy Agency resolution found Tehran at odds with its obligations under the Nuclear Non-Proliferation Treaty that Iran signed.

According to the resolution, Iran's past failings already set it up for consideration by the Security Council — though there was no immediate referral. Instead, the resolution asked IAEA members to look at the issue again at a future, unspecified meeting.

It wasn't the decisive rebuke desired by U.S. officials — who allege Iran has a secret illicit program to build a nuclear bomb and have long wanted Tehran reviewed by the Security Council and possibly punished with economic sanctions. While India switched its position to support the resolution, U.S. allies Russia, China and South Africa abstained from the vote.

The Bush administration focused on what it portrayed as an internationally backed choice that the resolution presents to Iran. Tehran can either, by resuming negotiations with Europeans, agree to cut off any weapons ambitions and go before the Security Council with that to mitigate its past activities. Or it can be hauled before the Security Council — as early as November, according to some diplomats — without showing new cooperation.

State Department spokesman Sean McCormack noted that Iran has control over what the IAEA reports to the Security Council and urged Tehran to discontinue "its defiant actions."

"What is contained in that report and the timing of that report will depend on what Iran does," he said.

Iran needs to "heed the signal" the resolution sent, McCormack said. "And that is, `Get back to the negotiating table.'" McClellan said, "There is a growing majority of nations that recognize Iran's noncompliance must be addressed."

Britain, France and Germany are the three key European countries that were negotiating with Iran to try to avert referral to the Security Council. Over the summer, Iran rejected a package of economic and security guarantees, walked away from the talks and resumed nuclear fuel production activity it had voluntarily suspended during negotiations.

McClellan said the United States "will not tolerate" Iran's "pattern of deception and concealment." Bush has refused to rule out a military strike on Iranian nuclear facilities if diplomacy fails, but has also said repeatedly that there is no plan to do so.