Iran has reportedly taken another step in its uranium enrichment programme, in defiance of international pressure.
Iran produces uranium gas at a plant near Isfahan
It has activated a second set of centrifuges - the machines used to enrich uranium - the semi-official Isna agency has said.
A BBC correspondent says Iran would need tens of thousands of centrifuges to make industrial-scale nuclear fuel.
The UN Security Council is to debate sanctions after Iran failed to meet an August deadline to stop enrichment.
Iran has not convinced the US and other Western states that its enrichment work is only aimed at generating electricity, and not acquiring nuclear weapons.
There is no doubt that the use of the second cascade of centrifuges will be seen as an act of defiance by the international community at what is a sensitive time, the BBC's Frances Harrison reports from Tehran.
The Iranian report suggested that scientists had injected gas into the second cascade.
Isna quoted its unnamed source as saying the second cascade's "product" had been obtained.
The source said the second cascade had been installed two weeks ago with the knowledge of UN nuclear inspectors.
"The International Atomic Energy Agency has been fully aware of the issue and the inspectors are present in Iran," the source said.
Iran's first cascade, consisting of 168 centrifuges, produced a small quantity of enriched uranium in February.
Iran has said it plans to install 3,000 centrifuges at its nuclear site in Natanz by the end of this year.