US National Security Adviser James Jones, however, disputed the IAEA's findings. Asked on CNN's "State of the Union" if Iran has the data to make a nuclear bomb, he said: "No, we stand by the reports that we've put out."
Two years ago, the US released a report suggesting that Iran has stopped work on its nuclear-weapons program in 2003. The Times emphasizes that other countries, including Britain and France, have begun to have doubts about this conclusion.
The authors of the so-called "secret annex" of the IAEA report acknowledge that their findings are not definitive and that further investigation is necessary.
But the report embodies a growing split within the nuclear agency on how hard to push Iran, The Times suggests.
Mohammed ElBaradei, head of the IAEA, has sought to emphasize progress in talks with Iran about its nuclear program.
In a visit to Tehran, he said: "I see that we are shifting gears from confrontation into transparency and cooperation."
In recent days, Iran has agreed to let IAEA inspectors visit its previously secret site near Qom on Oct. 25. It has also said that it is open to the idea of allowing Russia to enrich a stockpile of uranium that, international inspectors fear, could otherwise secretly be repurposed for weapons. In addition, Iran has agreed to further talks this month.
Mr. Jones agreed that Iran has taken positive steps. "What's happened with regard to Iran in the last couple of weeks has been very significant," Jones said.
Yet the White House is eager not to appear soft on Iran. Susan Rice, the US ambassador to the UN, effused to comment specifically on the IAEA report, saying "there are various assessments, and they don't all align" on NBC's "Meet the Press" Sunday.
Regardless, she said, the US' "whole approach is predicated on an urgent need to prevent Iran from obtaining nuclear weapons capacity."
"We're not interested in talking for talking's sake," she added.