Iran has slowed production of low-enriched uranium - IAEA

At the same time, IAEA chief Mohamed ElBaradei said that Tehran had slightly reduced the scale of its uranium enrichment activities, had allowed inspectors access to its heavy water reactor at Arak and allowed better monitoring of its uranium enrichment plant at Natanz.

The classified IAEA report was published on the website of the Washington-based Institute for Science and International Security, a non-partisan institution that focuses on bringing about greater transparency of nuclear activities worldwide and stopping the spread of nuclear weapons.

The long-awaited report found that the Islamic Republic had since June increased the number of its centrifuges by some 1,000 to 8,308, although not all of those were enriching uranium.

"The agency continues to verify the non-diversion of declared nuclear material in Iran," said the report.

Iran was still defying demands by the United Nations Security Council to suspend its enrichment related activities and heavy water related projects, the nuclear watchdog said.

"There remain a number of outstanding issues which give rise to concerns," the report said, adding that the agency had requested Iran "to provide more substantive responses and to provide the agency with the opportunity to have detailed discussions with a view to moving forward on these issues."

The IAEA reiterated its call for Iran to implement the Additional Protocol , which allows for short-notice inspections by the agency's monitors beyond a country's declared nuclear sites.

On the issue of Western intelligence that showed Iran was pursuing information about weaponizaiton efforts and a military nuclear program, the report said that intelligence "appears to be generally consistent, and is sufficiently comprehensive and detailed that it needs to be addressed by Iran."

Iran has called the Western intelligence "fabricated", and has demanded access to the documentation.

The IAEA said that by limiting the availability of the information to Iran, Western powers were making it more difficult for the agency to carry out discussions with Iran on the matter.

The agency noted that the agreement on better camera surveillance and data collection at Natanz came after it complained that Iran's vast expansion of centrifuge operations since 2008, without corresponding monitoring upgrades to keep pace, left the agency unable to verify that nothing was being diverted for military purposes.

It also said that Iran had allowed IAEA inspectors to revisit the Arak site this month after barring access for a year. Iran told the agency that the Arak complex was 63 percent complete and the reactor vessel would be installed in 2011.

Iran expects to load nuclear fuel into its Bushehr nuclear power plant in October or November of this year, and in view of that, the IAEA said it had installed a containment and surveillance system there this month.

The report comes as the United States, Britain, France, Germany, China and Russia prepare to meet next week to discuss Iran's nuclear program. The four Western countries are hoping to persuade Beijing and Moscow on the need for tougher sanctions against Tehran, in order to curb its nuclear drive.