In fact, the team could find no centrifuge machines "deployed in a production environment" that used such narrow tubes.

It has tried repeatedly during the negotiations that started in 2003 to continue what it has called "research" involving a limited number of fast-spinning centrifuge machines.

But they said it would be virtually impossible for him to have removed large centrifuge machines from the country's nuclear labs and ship them out of the country without the military knowing.

Mounted inside the aluminum casing, rotors are the spinning part of the centrifuge machine.

Once completed, the commercial plant will use approximately 11,500 centrifuge machines to generate 3.8 million separative work units (SWU) a year.

After the cease-fire, atomic energy agency inspectors found a secret plant near Baghdad capable of manufacturing up to 1,000 centrifuge machines annually.

"Iran has started another stage of injecting hexafluoride gas into centrifuge machines," ISNA quoted him as saying.

He was selling material and information to the Iraqis which assisted them in developing a viable centrifuge machine," the official said.

The team was unable to developed the centrifuge machine according to Khan's stolen blueprints.

The initiative is aimed at encouraging Iran to return to a freeze of its nuclear activities, including turning off the fast-spinning centrifuge machines that produce enriched uranium.