PARIS, Aug. 30 -- The United Nations nuclear watchdog agency gave an upbeat assessment of Iranian cooperation with international inspectors in a new report Thursday that could make it more difficult for the United States to win tougher U.N. sanctions against Iran.
The report by the International Atomic Energy Agency in Vienna also concluded that while Iran continues to enrich uranium in violation of U.N. Security Council resolutions, its fuel enrichment plant has produced "well below the expected quantity for a facility of this design." The quality of the uranium also was lower than expected, the IAEA said.
The report praised Iran for taking "a significant step forward" by agreeing to a new work plan and timelines for resolving numerous questions about the history of its nuclear program. Separately, U.N. officials said that Iran had slowed construction of a new plutonium-fuel reactor in Arak.
Iran claims that its nuclear program is entirely peaceful and intended to generate electricity, while the United States and numerous other Western countries contend it is secretly aimed at developing nuclear weapons. The report suggests that if Iran adheres to the program and timelines, the agency could resolve its remaining questions about the nature of the country's nuclear program by the end of the year and close the file.
"For the first time in a couple of years, we have been able to agree with the Iranians on a working arrangement, on how to resolve the outstanding issues," the U.N. agency's deputy director, Olli Heinonen, told reporters in Vienna. "What Iran is now facing is actually a litmus test" on whether it will deliver what it has promised, because its failure to do so in the past triggered Security Council action, Heinonen said.
If the IAEA concludes that Iran has not engaged in a covert program to develop nuclear weapons, it could raise new questions about the quality of U.S. intelligence in the Middle East. The United States made the case for going to war against Iraq based on claims that Saddam Hussein had programs to develop nuclear technologies and other weapons of mass destruction, but U.S. forces found no evidence of such programs after invading the country.
Longtime observers of Iran's program were struck by the report's revelations of slow progress of uranium enrichment. Iran appears to be running well behind its own self-imposed schedule for building new centrifuge machines, and its existing machines are operating well below capacity.
Based on IAEA figures, Iran is producing low-enriched uranium at a rate of about 31 pounds a month, compared with an expected rate of nearly 200 pounds a month, according to an analysis by the Institute for Science and International Security, a Washington-based research group.
The low output suggests that Iran is either experiencing technical difficulties or has perhaps decided to slow production to "forestall negative reactions that would lend support for further sanctions," the institute said in a report released Thursday. Low-enriched uranium is used for making nuclear power and cannot be converted for weapons use unless it undergoes further processing.
A senior Iranian official, Mohammad Saeedi, deputy secretary of Iran's Supreme National Security Council, welcomed the IAEA report, telling the state-run news agency IRNA that it "put an end to all U.S. baseless allegations" about his country's nuclear program and "once again endorsed the authenticity of the statements of the Islamic Republic of Iran."
But the report also gave ammunition to Iran's critics, who noted that the country has not stopped its uranium enrichment, as demanded by the U.N. Security Council. It imposed two rounds of limited sanctions against Iran in December and March.
The United States is pushing for tougher sanctions, and some U.S. hard-liners advocate possible military actions if Iran does not halt enrichment. They also cite the belligerence of President Mahmoud Ahmadinejad, his threats against Israel, and U.S. claims that Iran is supplying militants in Iraq with weapons, money and training to fight U.S. forces.
"For the most part, Iran has made only promises," U.S. Ambassador to the IAEA Gregory L. Schulte said in a statement Thursday. The report "indicates that Iran has not suspended its enrichment related activities, which is a violation of U.S. Security Council resolutions." Such a step is necessary "for the international community to gain confidence that Iran's nuclear activities are exclusively for peaceful purposes."
France said that it would continue pursuing sanctions as long as Iran continued enriching uranium, and a statement by the British Foreign Office said that it also lacked confidence in Iran's nuclear intentions.
The IAEA report, which covers developments in the agency's dealings with Iran since May, will be discussed at a meeting of the agency's 35-member board on Sept. 10 in Vienna.
The document lists "outstanding issues" that need to be resolved for the agency to assess the nature of Iran's nuclear program, including alleged links between Iran's uranium enrichment, high-explosives testing and the design of a missile capable of flying above the atmosphere and then reentering it. Some U.S. officials have cited the links as evidence that Iran's nuclear program has a weapons goal.
The report cites several contentious issues that have been resolved recently through a renewed dialogue with Iran and the work program that Iranian and U.N. officials agreed to in a series of meetings in July and August.
Warrick reported from Washington.
On August 27, Iran published public information report about its nuclear program, thus unveiling a part of outstanding issues still in discussion with  (IAEA). In this document, Tehran provide clarifications about plutonium experiments and shows signs of cooperation in clearing up questions about its efforts to acquire nuclear technology. The IAEA issued a new report on August 30, and distributed copies of its report ahead of a September 10 meeting of the organization's 35-member board.

This report also reflects findings about a work plan concluded on August 21. The United Nations nuclear watchdog report praised Iran for agreeing to a new work plan and planning to resolve numerous questions about its nuclear program. 

Mohamed ElBaradei, the IAEA director general, said in reaction to these reports: "This is the first time Iran is ready to discuss all the outstanding issues which triggered the crisis in confidence. It's a significant step."

The assessment of Iran nuclear cooperation could make it more difficult for the United States and its allies to win tougher U.N. sanctions against Iran. 

In Iran, the Deputy Secretary of the Supreme National Security Council (SNSC) for International Affairs, Mohammad Saeedi, said that the IAEA report « put an end to all US baseless allegations on Iran's separation activities and reprocessing plutonium.»