The International Atomic Energy Agency shared the intelligence with 35 nations on Tuesday, but the Iranian representative to the organization says the information was fabricated.
Gregory L. Schulte, the chief U.S. representative to the IAEA, said the evidence shows Iran has a weapons program.
The two spoke separately to reporters after the presentation by the IAEA, one day after the U.N. nuclear watchdog issued a report saying that Iran has stonewalled its attempts to probe allegations that it drew up plans and conducted experiments for a nuclear arms program.
Meanwhile, France said Tuesday it would push for more sanctions against Iran.
"We have no other choice than to work in the days and weeks to come toward a new Security Council sanctions resolution," French Foreign Ministry spokesman Eric Chevallier said.
He called the IAEA findings "very worrisome."
White House spokesman Gordon Johndroe also spoke Monday of "the possibility of new sanctions" if Iran continues to defy the U.N.
However, Russia and China, who like the U.S. and France have veto power over U.N. Security Council resolutions, would likely resist a fourth round of sanctions against Iran. Britain, the fifth veto-wielding member of the Security Council, is aligned with the U.S. and France.
The Security Council has already imposed three sets of sanctions on Iran over its nuclear defiance.
The IAEA's report said Iran has now amassed a third of the amount of enriched uranium it could reprocess into the material for the fissile core of a nuclear weapon should it choose to do so. But U.N officials familiar with the report emphasized that Iran - whose known nuclear programs are under IAEA supervision - has shown no indication it wanted to go that route.
The U.S. and its allies allege that Iran wants to develop its uranium enrichment program to make nuclear weapons. But oil-rich Iran insists it only wants to make nuclear energy, and IAEA oversight and inspections of its known enrichment program has not found any evidence that contradicts that.
China said Tuesday that imposing further sanctions on Iran will not resolve the nuclear impasse.
"I don't think sanctions are the way out," Chinese Foreign Ministry spokeswoman Jiang Yu said.
But Jiang also said China hoped Iran would keep cooperating with the IAEA.
"The solution of the Iranian nuclear issue is negotiation and dialogue," she told a regular news briefing. "We hope the relevant parties will step up diplomatic efforts and settle the issue peacefully through dialogue and negotiations."