"Iran has not suspended its enrichment related activities," the International Atomic Energy Agency (IAEA) said in reporting on Iran's compliance with a UN call in March to stop enrichment work, which makes fuel for civilian reactors but also atom bomb material.

Iran is feeding at an underground facility in Natanz 1,312 centrifuge machines, "operating simultaneously" in eight cascade arrays of 164-machines each, with the uranium gas need to make enriched uranium, said the confidential report by IAEA director Mohamed ElBaradei, a copy of which was obtained by AFP.

Iran could reach its goal of industrial scale production with 3,000 centrifuges running by the end of June, a senior official close to the IAEA said.

In its report, the IAEA said its ability to monitor Iran's nuclear program "has deteriorated" due to lack of access.

"Because the agency has not been receiving for over a year information that Iran used to provide ... the agency's level of knowledge of certain aspects of Iran's nuclar related activities has deteriorated," the IAEA said.