The tone of the language suggesting Tehran continues to stonewall the U.N. nuclear monitor revealed a glimpse of the frustration felt by agency investigators stymied in their attempts to gain full answers to suspicious aspects of Iran's past nuclear activities.
A senior U.N. official familiar with the investigation into Iran's nuclear program said none of the dozens of agency reports issued in that context had ever been as plain spoken in calling Tehran to task for not being forthright. He agreed to discuss the report only if granted anonymity because he was not authorized to comment to the media.
Iran has described its cooperation with the agency's probe as positive, suggesting it was providing information requested by agency officials.
Ali Ashgar Soltanieh, Iran's chief delegate to the IAEA, said as much again Monday, telling The Associated Press that the report described "the peaceful nature of our nuclear actions."
"The Americans failed ... in shameful attempts" to co-opt the agency into delivering anti-Iranian findings, he said.
He noted a paragraph in the report saying that agency experts had been given access to all declared nuclear material in Iran and verified that all of it was accounted for.
But Gregory L. Schulte, his U.S. counterpart, suggested the report was a strong indictment of Iran's defiance of the international community's efforts to get answers about troubling parts of its nuclear program, noting it "details a long list of questions that Iran has failed to answer."
"At the same time that Iran is stonewalling its inspectors, it's moving forward in developing its enrichment capability in violation of Security Council resolutions," Schulte told the AP.
He described parts of the report as a "direct rebuttal" of Iranian claims that all nuclear questions had been answered.
"The nuclear watchdog agency's Iran report, which will be formally presented next week, places the burden squarely in the lap of the U.N. Security Council to consider next steps, since the report concludes that there still unanswered questions about a military dimension of Iran's uranium enrichment," said CBS News foreign affairs analyst Pamela Falk from the U.N.
"Because it makes everyone justifiably nervious that Iran is moving forward on its nuclear program, and because Russia and China just inked a billion dollar deal to cooperate on nuclear energy," Falk said, "we will surely begin to hear new proposals on how to deal with the nuclear issue from U.S. presidential candidates."
"Iran has defied three U.N. Security Council resolutions which demand a freeze of its uranium enrichment program, and U.S. policymakers are beginning to look to more multilateral negotiation with Russia and China after the U.S. presidential election in order to find a way out of Iran's advancing nuclear program," Falk said.
U.S. intelligence says Iran stopped work on nuclear weapons in 2003 but some other nations believe such activities continued past that date. The report noted Iran continued to deny such allegations.
Obtained by the AP, the restricted report forwarded to the U.N. Security Council and to the 35 board members of the IAEA said Iran remains defiant of the council's demands that it suspend uranium enrichment.
Shrugging off three sets of council sanctions, Iran has expanded its operational centrifuges - machines that churn out enriched uranium - by about 500 since the last IAEA report, in February, the new report said.
In announcing major progress in his government's push for nuclear power, Iranian President Mahmoud Ahmadinejad said last month that Iranian scientists were putting 6,000 new uranium enriching centrifuges into place and testing a new type that worked five times faster.
The IAEA report noted Iran now had only 3,500 centrifuges and said the few advanced machines actually running were only in a testing phase. Still the senior U.N. official said Iran's goal of 6,000 machines running by the summer was "pretty much plausible."
Uranium can be used as nuclear reactor fuel or as the core for atomic warheads, depending on the degree of enrichment.
Running smoothly, 3,000 centrifuges could produce enough nuclear material for a bomb within 18 months. But Iran insists it is only working to produce fuel for reactors that will generate electricity and says it has a right to conduct enrichment for such purposes under the Nuclear Nonproliferation Treaty.
In addressing whether Iran was complying with IAEA requests, the report appeared to come down on the side of the U.S. "Iran has not provided the Agency with all the information, access to documents and access to individuals necessary to support Iran's statements" that its activities are purely peaceful in intent, it said.
"The Agency is of the view that Iran may have additional information, in particular on high explosives testing and missile related activities which ... Iran should share with the agency," the report said. It was referring to two alleged sets of tests that IAEA officials say could be linked to a nuclear weapons program.
The allegations of nuclear military programs "remain a matter of serious concern," the report said. Suggesting fears of clandestine weapons activities remain, it added: "Clarification of these is critical to an assessment of the nature of Iran's past and present nuclear program."
Iran already rejected evidence provided by the U.S and other IAEA board members on alleged weapons programs in February, but then promised to revisit the issue before the agency's next board meeting in a week.
Intelligence received by the IAEA in its investigations, as well as from the U.S. and other agency board member nations, suggest Iran experimented with an undeclared uranium enrichment program that was linked to a missile project and drew up blueprints on refitting missiles to allow them to carry nuclear warheads.
The intelligence also suggested Iran was researching construction of an underground site that apparently could be used to test fire nuclear bombs and ordered "dual use" equipment from abroad that could be part of an atomic weapons program.
Additionally, Iran possesses diagrams showing how to mold uranium metal into the shape of warheads.
Its nuclear work has been under IAEA investigation since 2003, when a dissident Iranian group revealed the existence of a clandestine enrichment program.