VIENNA — Iran has done next to nothing to respond to international demands that it halt its uranium enrichment program and provide information about its nuclear activities, according to a confidential report by the International Atomic Energy Agency.

The report, which is expected to be sent to the U.N. Security Council in two weeks for debate over possible sanctions, stops short of outright condemnation of Tehran's activities. But it raises grave doubts about Iran's assurances that its program is solely for civilian energy purposes.

Iran's failure to provide requested information meant that the U.N. atomic watchdog agency also could not rule out that Tehran was hiding nuclear materials or activities in violation of the Nuclear Nonproliferation Treaty, said the report by the agency's director-general, Mohamed ElBaradei. It stopped short of saying that Iran's aims might not be peaceful, which would have been an extremely serious finding.

In Iran's favor, ElBaradei found no evidence that nuclear material had been diverted toward building a weapon.

Countries that sign the nonproliferation treaty must disclose all nuclear material to the International Atomic Energy Agency, or IAEA.

"To clarify these uncertainties, Iran's full transparency is still essential," said ElBaradei's report, a copy of which was obtained by The Times.

The report, submitted Monday to the IAEA's governing board, also noted that Iran had failed to take any of the steps demanded by the board at its meeting this month.

To the contrary, Iran is testing a series of 20 centrifuges, a process essential to developing a full-scale capacity to enrich uranium.

"They were asked to suspend all enrichment activities, they started small-scale research and development; they were asked to ratify and implement the additional protocol, they suspended it; they were asked to take transparency measures," but failed to do so, said a senior official familiar with the IAEA's Iran probe.

The additional protocol was meant to give weapons inspectors broader latitude to examine workshops where nuclear processing machinery is made and to inspect a wider range of sites.

The report, drafted for next week's meeting of the 35-nation IAEA board, will play a key role in determining the international community's next steps to try to persuade Iran to halt its nuclear program.

After review by the board, it will be sent to the Security Council, which is expected to start considering the matter the week of March 13, U.S. diplomats said.

The IAEA board had already reported Iran to the U.N. Security Council earlier this month, but agreed to delay the delivery of its report until after the March 6 IAEA board meeting. The hiatus was a compromise to placate China and Russia, which had been reluctant to report Iran to the council, and to give diplomacy another chance.

Iran responded to that chance by trying to answer some of the weapons inspectors' questions, and by making available to inspectors a scientist who ran a research laboratory at the Lavisan-Shian military site.

The moves appear to be aimed at making it more difficult for the Security Council to take any strong actions against Iran.

Tehran also is in negotiations with Moscow about a joint uranium enrichment facility in Russia. Iran thus far has been unwilling to give up its right to enrich uranium within its own borders, as the U.S., Europe and Russia have demanded.

"Iran has a track record that before every board meeting they try to give a little to the agency in the hopes that they will get undue credit for it in the agency's report," said a U.S. diplomat who had reviewed the document.

Agency reports over the last three years show that Iran has been working steadily both to obtain and manufacture the equipment to perform uranium enrichment and to perfect the delicate enrichment process.

"Sooner or later they will get this knowledge to run these machines — it depends how hard they work and when they get the experience," said a senior official familiar with the IAEA probe.

Uranium must be enriched to be used as a fuel in nuclear power plants. Higher levels of enrichment are required for use in a bomb.

Most of the agency's questions about possible military links to Iran's program remain unanswered.

The report says Iran has begun renovating its pilot fuel enrichment plant at Natanz and putting in place the first of 3,000 centrifuge machines in a larger fuel enrichment facility at the site, which it expects to complete by the end of the year.

In February, Iran fed uranium gas into a machine. In mid-February, it began to feed gas into a series of 10 linked centrifuges known as a cascade. On Feb. 22, Iran began to test a 20-machine cascade. These activities are all under IAEA surveillance.

However, the IAEA can no longer tell how quickly Iran might be assembling and testing new centrifuge machines, because it can no longer visit those sites. Experts dispute exactly how long it would take Iran to produce enough highly enriched uranium to make a bomb, but there is little disagreement that if Iran continues to work on perfecting the enrichment process, it is a matter of no more than a few years.