The document, which Iran said came from a black market offer in 1987 that it never acted upon, gives "procedural requirements for ... the casting and machining of enriched, natural and depleted uranium metal into hemispherical forms," an International Atomic Energy Agency report said Friday.

The IAEA report "does not reveal a breach of trust in this matter, but settles for mentioning the complete transparence of Iran," Iranian Atomic Energy Agency vice chairman Mohammad Saidi said on state television.

Disclosure of the document raised new concerns about the nuclear programme, which Tehran says is a peaceful drive to produce electricity but the United States and Europe fear could be hiding the development of atomic weapons.

The report, which IAEA chief Mohamed ElBaradei is to present to a board of governors' meeting on Thursday, said Iran is still denying access to sensitive sites and information.

The governors will consider whether to refer Iran to the UN Security Council for possible sanctions for not complying with the Non-Proliferation Treaty.