TEHRAN (Reuters) -- A team from the UN nuclear watchdog is inspecting a nuclear site in Iran that has heightened Western fears of a covert program to develop atomic bombs, the semi-official Mehr news agency reported.
Iran added to global concerns over its nuclear intentions in September by revealing the existence of the site in central Iran after Western spy services penetrated a three-year veil of secrecy.
"The inspectors...visited the facility in central Iran. They are expected to visit the site again," Mehr reported, without giving a source.
There was no immediate confirmation from the International Atomic Energy Agency (IAEA).
The IAEA inspectors arrived in Iran early on October 25 to examine the site, under construction 160 kilometers south of Tehran.
Refined uranium can be used to fuel nuclear power plants and also to provide material for bombs if enriched further.
Iran, which says it wants only peaceful nuclear energy, agreed to open the new site to monitoring at talks with six world powers held in Geneva on October 1.
But a second understanding struck in Geneva stumbled on October 23 when Iran cast doubt on a plan to send abroad much of its enriched uranium reserve for processing into special fuel for nuclear medicine in Iran.
World powers regard the two steps as litmus tests of Iran's stated intent to use enriched uranium only for civilian purposes and a basis for follow-up talks on curbing enrichment itself, which would bring Iran trade and technology rewards in return.
Influential Iranian lawmakers have criticized the UN-drafted nuclear fuel agreement, in comments echoed by an Iranian diplomat on October 25.
Abolfazl Zorehvand, a former ambassador to Italy, said the plan amounted to a kind of suspension of Iran's enrichment work -- a demand the Islamic state has repeatedly rejected.
"If we want to enrich this amount again it would take at least 18 months. During these 18 months they will have time to pressure Iran again and push us in the direction they want to," the official IRNA news agency quoted Zorehvand as saying.
"These signals from the West create mistrust," he said.
Iran has said the centrifuge plant being built in a military compound buried inside a mountain near the Shi'ite holy city of Qom will refine uranium only for civilian nuclear energy.
Western diplomats and analysts say the site's capacity appears too small to fuel a nuclear power station but enough to yield fissile material for one or two nuclear warheads a year.
The four-strong team from the International Atomic Energy Agency's safeguards division, led by Herman Nackaerts, who oversees the Middle East region including Iran, declined comment to reporters in Vienna before boarding their flight.
Their stay in Iran is likely to last several days.
The inspectors intend to compare engineering designs to be provided by Iran with the actual facility, interview employees, and take environmental samples to verify the site has no illicit military dimension.