A new quarterly report by the International Atomic Energy Agency (IAEA) says Iran has installed about 1,000 advanced uranium-enrichment centrifuges and is set to test them.
The new centrifuges are three to four times more effective than existing centrifuges Iran uses to produce medium-enriched uranium, which Western powers fear eventually could be further enriched to produce nuclear bomb material.
But the IAEA, which acts as a nuclear watchdog for the UN, also reported on August 28 that Iran's stockpile of medium-enriched uranium has grown little over the past three months because some production has been converted into reactor fuel.
The report also says Iran has started making fuel assemblies for a planned heavy-water reactor that could yield plutonium for nuclear weapon use.
The new IAEA report is the first since new Iranian President Hassan Rohani was elected in June and mainly covers activities that took place before he took office on August 3.
Signs Of Changed Approach?
The IAEA also announced that a new round of talks with Iranian officials over Tehran's disputed nuclear program was scheduled for September 27. The talks in Vienna will be the first such meeting since Rohani was elected.
Western countries that accuse Tehran of trying to secretly develop nuclear weapons are expected to scrutinize the talks for signals on whether Iran is more willing to compromise in the decades-old dispute.
A former nuclear envoy himself, Rohani has pledged more transparency and less confrontation in dealings with the IAEA and with world powers.
Iran and IAEA delegates last met in May. They did not reach a breakthrough that would allow the UN agency to resume a long-stalled investigation into possible military dimensions of Iran's nuclear program.
Iran, which currently has some 15,000 centrifuges producing medium-enriched uranium, denies it is seeking to develop nuclear weapons. It says its nuclear program is entirely for peaceful production of nuclear energy.
With reporting by Reuters, AP, and AFP