The International Atomic Energy Agency (IAEA) report, obtained by AFP, also detailed how Iran is pressing ahead with research levels of uranium enrichment -- a process the West fears could be diverted to make a nuclear bomb.
Despite the threat of UN sanctions over Tehran's refusal to hold back its nuclear program, Iranian President Mahmoud Ahmadinejad announced on Tuesday that Iran eventually planned to install tens of thousands of uranium-enriching centrifuges to produce nuclear fuel.
The IAEA report said the agency is investigating traces of plutonium found in containers at a waste storage site at Karaj in Iran.
Iran has been "requested to provide further clarification" of highly enriched uranium as well as plutonium particles found at Karaj and responded to this request on Tuesday, the report said.
A senior UN official told reporters that the Iranian response had come too late to be analysed before an IAEA meeting next week in Vienna that will review the Iranian nuclear program.
The official said an overall problem remains in getting full and timely Iranian cooperation with the IAEA investigation into its atomic program that began in February 2003.
Iran needs "to do more" to clear up "the ambiguities particular to some of the alleged military aspects of the program," the official said.
According to the report, progress in this regard "is a prerequisite for the agency to be able to confirm the peaceful nature of Iran's nuclear programme."
Ahmadinejad announced on Tuesday that the ultimate aim of Iran's atomic drive was to install some 60,000 uranium-enriching centrifuges to produce nuclear fuel.
In Washington, US State Department spokesman Sean McCormak said the announcement was a "cold jolt" to doubters of Tehran's nuclear arms ambitions.
And at the United Nations, US Ambassador John Bolton said: "President Ahmadinejad's statements and the draft IAEA report both demonstrate the urgency for the Security Council to act on Iran. Sanctions are obviously the only means to get Iran's attention."
Ambassadors from Germany and the UN Security Council's permanent members -- Britain, China, France, Russia and the United States -- are currently deadlocked in talks to agree on a European draft resolution urging nuclear and ballistic missile-related sanctions against Iran.
The draft put forward by Britain, France and Germany includes travel bans and financial restrictions on Iranian scientists working on the nuclear and missile programs.
It is viewed as too tough and as counter-productive by Russia and China, which both maintain close energy and trade ties with Tehran while Washington is pushing for even tougher sanctions.
Iran has installed a new cascade, or production line, of centrifuges at its uranium enrichment facility in Natanz in the center of the country, and now has two cascades of 164 centrifuges each running, as well as several smaller cascades.
Iran from August 13 to November 2 fed "a total of approximately 34 kilograms" of feedstock uranium gas into centrifuges in Natanz, producing a small amount of uranium enriched to low levels, the report said.
It did not detail how much uranium was produced but said enrichment levels seemed to be below five percent, nowhere near the 90 percent level needed to make atom bombs.
The research uranium enrichment facility in Natanz, where Iran wants eventually to build a large-scale facility with over 50,000 centrifuges, is monitored by the IAEA but the agency is also investigating possibly military-related nuclear work by Iran elsewhere.
One such site was a physics laboratory at Lavizan in Tehran that was razed in 2004 before IAEA inspectors could visit.
"Iran has not yet responded to the agency's long outstanding requests for clarification concerning and access to carry out further environmental sampling of equipment and materials related to the Physics Research Centre (PHRC) nor has Iran provided the agency with access to interview... (a) former head of the PHRC," the report said.
The agency is also waiting for information on high explosives testing and the design of a missile re-entry vehicle, the report said, adding that Iran had not provided "sufficient clarification" on experiments designed to separate out plutonium.

Copyright AFP (Agence France-Presse), 2006