The U.N. nuclear agency says Iran has rapidly ramped up production of higher-grade enriched uranium over the last four months, in a confidential report that feeds concerns about how quickly the Islamic Republic could produce an atomic bomb.
Friday's report by the International Atomic Energy Agency also said Iran had failed to give a convincing explanation about a quantity of missing uranium metal. Diplomats have said the missing amount could be used for experiments used to arm a warhead.
In a confidential document, the agency also reported on its failed mission to Tehran this week to try and get Iran to respond to allegations of research relevant for the development of nuclear weapons.
Iran thwarted investigation into nuclear program, UN watchdog says
The setback increased worries about a downward spiral towards conflict between Iran and the West, and sent oil prices higher.
"The Agency continues to have serious concerns regarding possible military dimensions to Iran's nuclear program," the Vienna-based U.N. body said in its latest quarterly report about Iran's atomic activities.
Iran insists it is not interested in nuclear weapons and says all of its activities are meant either to generate energy or to be used for research.
Reuters and The Associated Press contributed to this report.
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