The UN has a "very strong case" for imposing more sanctions on Iran over its nuclear program, US Secretary of State Condoleezza Rice said Friday.
She said a new report authored by the International Atomic Energy Agency saying Tehran has failed to fully cooperate with UN atomic investigators is good reason for the Security Council to consider a third round of sanctions.
The report said Iran also failed to answer key questions about its nuclear past.
"It hasn't answered questions about past activities in covert programs that they say they didn't have," Rice said.
"I think that this report demonstrates that whatever the Iranians may be doing to try to clean up some elements of the past, it is inadequate, given their current activities, given questions about their past activities," she said.
"If you just look at that record, I would have to say there is a very strong case for moving forward on the Security Council resolution."
The US wants quick action to punish Iran in light of the findings of the report, the secretary of state added.
Rice spoke days before senior diplomats from the five permanent members of the UN Security Council and Germany meet in Washington to discuss a new resolution. All have agreed on a draft.
Earlier, Undersecretary of State Nicholas Burns said he will meet Monday with diplomats from world powers that have twice punished the oil-rich nation over its nuclear drive, and wants the UN Security Council to approve new penalties soon afterward.
"We find Iranian performance to be lacking," Burns told reporters at the State Department. "As a result of this it's our firm belief that there is all the more reason now for the Security Council to pass a third sanctions resolution."
The US wants the Security Council to begin debate next week. Burns would not predict how long debate would last, and would not rule out that the current package of proposed punishments could change. The proposed package slightly expands and strengthens previous penalties, but is weaker than the United States had wanted.
Burns is the top US negotiator on a carrot-and-stick package proposed by the UN Security Council's five permanent states, which are all nuclear powers, plus Germany. Iran has rebuffed the offer, and has brushed off the Security Council's penalties.
Iran's sometime allies and trade partners Russia and China, which hold veto power at the Security Council, oppose very harsh measures. Burns said the new round of sanctions would pinch Iran, but he argued more strongly that failing to act would make the Security Council look weak.
The report Friday from the UN's International Atomic Energy Agency confirmed that Iran has continued to enrich uranium in defiance of repeated UN council resolutions demanding that it suspend the uranium centrifuge program, which could produce both civilian nuclear fuel and the material for a nuclear bomb.
Iran says the US and its allies provided false information saying Tehran's missile and explosives experiments were part of a nuclear weapons program, the International Atomic Energy Agency said Friday.
The UN body has demanded that Iran freeze the enrichment program, which can generate both nuclear fuel and the fissile core of warheads. Iran claims its program is peaceful and insists it has the same right to enrichment technology as nuclear nations such as the United States.
The 11-page report gave Iran a relatively clean bill of health on explaining the origin of traces of enriched uranium in a military facility; experiments with polonium, which can also be used in a weapons program; and purchases on the nuclear black market.
But it said Tehran had rejected as irrelevant some material forwarded by the agency that purportedly shows it working on tests of missile trajectories and high explosives, and research on a missile re-entry vehicle — activities that would most likely be part of weapons development.
Questions also remained on how and why Iran came to possess diagrams showing how to mold uranium metal into warhead shape.