Iran has lifted a yearlong ban and allowed U.N. inspectors to visit a nearly completed nuclear reactor as well as granting greater monitoring rights at another atomic site, diplomats said Thursday, AP reported.



International Atomic Energy Agency inspectors visited the nearly finished Arak heavy water reactor last week, the diplomats told The Associated Press. Separately, they said Iran agreed last week to IAEA requests to expand its monitoring of the Natanz uranium enrichment site, which produces material for nuclear fuel that can be further enriched to provide fissile material for warheads.



The diplomats demanded anonymity because their information was confidential.



The agency had been seeking additional cameras and inspections of the Natanz site, to keep track with the rapidly expanding enrichment program which - if modified - can make the fissile core of warheads.



Iran's stonewalling had raised agency concerns that its experts might not be able to make sure that some of the enriched material produced at Natanz is not diverted for potential weapons use.



Since its clandestine enrichment efforts were revealed more than six years ago, Iran has steadily increased activities at its cavernous underground facility at Natanz, a city about 300 miles (500 kilometers) south of Tehran, shrugging off three sets of U.N. Security Council sanctions and rejecting talks meant to entice it to mothball the activity.



A June IAEA report said nearly 5,000 centrifuges were now enriching at Natanz - about 1,000 more than at the time of the last agency report, issued in February - with more than 2,000 others ready to start enriching. A new report due in the next week or so is expected to confirm that operations continue to expand - along with Tehran's potential capacity to produce weapons-grade uranium.



Most experts estimate that the more than 1,000 kilograms (2,200 pounds) of low-enriched uranium Iran had accumulated by February was already enough to produce enough weapons-grade material through further enrichment for one nuclear weapon.



Tehran says it has a right to enrich, insists it is not interested in making weapons and has no intention of reconfiguring its operations from churning out nuclear fuel-grade material to highly enriched uranium suitable for nuclear arms.



Before lifting the ban on visiting Arak, Tehran had repeatedly refused IAEA inspection requests, despite warnings by the agency that its stance contravened mutual agreements.



Western countries have repeatedly called on Iran to stop construction of the reactor, fearing it could be used as a second track toward building a warhead. When finished, say experts, Arak could produce enough plutonium for a nuclear weapon each year.