The International Atomic Energy Agency (IAEA) said in the report, obtained by journalists on Tuesday, that Iran got the material from Asian suppliers.
"Iran has acknowledged that, contrary to earlier statements, it had imported some magnets relevant to P2 centrifuges from Asian suppliers," read the report.
There were also indications Iran's interest in the centrifuges, which can produce bomb-grade uranium twice as quickly as earlier P1 centrifuges, was more than "research and development" on a small amount of centrifuges as it had told the IAEA.
According to the IAEA, Iran said a private Iranian company had made inquiries through a European intermediary for 4000 magnets for P2 centrifuges, enough to equip 2000 centrifuges. The machines cannot enrich uranium without these magnets.
"Iran has acknowledged that, contrary to earlier statements, it had imported some
magnets relevant to
P2 centrifuges from Asian suppliers"
"The owner of the private company acknowledged that he had mentioned to the intermediary the possibility of future procurement of higher numbers of P2 centrifuge magnets beyond the 4000," the report said, noting Iran said that a promise of future orders was made to get a better price.
The issue of the centrifuges has been a key one in the IAEA probe into Iran's nuclear programme since earlier this year.
Iran had left out its P2 research from an October declaration it said was the full story of its nuclear programme, an omission IAEA chief Muhammad al-Baradai called a setback.
"On issue after issue, Iran's story doesn't seem to check out and raises continued questions about Tehran's commitment to full cooperation," Jon Wolfsthal, deputy director for non-proliferation at the Carnegie Endowment for International Peace, said of the report.
A US government official, who declined to be named, said: "The more the IAEA looks, the more they find and the more Iran says 'Oops, we need to amend our declaration'."
"The jury is out on whether the programme has been dedicated exclusively for peaceful purposes"
But al-Baradai, who authored the report, earlier warned it would be premature to say it was clear Iran's programme was not peaceful in nature.
"The jury is out on whether the programme has been dedicated exclusively for peaceful purposes," al-Baradai said.
Washington accuses Iran of pursuing a nuclear arms programme. Tehran denies this, saying its nuclear programme is only for power generation.
However, the report praised Iran for "providing access to locations in response to agency requests, including workshops situated at military sites".
But inspections were delayed in some cases due to discussion of terms of access to defence industry sites.
The UN has been investigating Iran since an exiled Iranian opposition group reported in August 2002 that Tehran was hiding a massive uranium enrichment plant at Natanz and other sites from UN inspectors.