Updated

Iran (search) has acknowledged it worked with small amounts of plutonium, a possible nuclear arms component, years longer than it previously admitted, according to a confidential U.N. report made available Wednesday to The Associated Press.

The report, which could be delivered as early as Thursday to a board meeting of the International Atomic Energy Agency (search), also said Tehran received sensitive technology that can be used as part of a weapons program earlier than it originally said.

Marked "highly confidential," the report to the IAEA was made available by a diplomat accredited to the agency who demanded anonymity because he is not authorized to release such information to the media.

The three-page report took stock of the present stage of a two-year inquiry of Iran's nuclear activities. It suggested that some of the investigations were stalled, saying, the IAEA "still needs to understand" the nature, dates and number of contacts between Iranian officials and nuclear black market intermediaries that supplied Tehran with much of its advanced technology — including centrifuges for uranium enrichment.

The IAEA first revealed that Iran produced small amounts of plutonium as part of covert nuclear activities back in November 2003, more than a year after revelations that Iran had run a secret atomic program led the agency to start probing the country.

Plutonium (search) can be used in nuclear weapons, but it also has uses in peaceful programs to generate power, which is what Iran says is the sole purpose of its nuclear activities.

The agency has not linked the laboratory-scale experiments to weapons activity, nor has it said that any other parts of the program — including ambitious efforts to be able to enrich uranium — constituted evidence that Tehran has been trying to make weapons. But at the time, it criticized Iran for not voluntarily revealing its plutonium work and other activities that could be linked to making nuclear arms.