Iran's top security body said on Friday the cause of an incident and fire at the Natanz nuclear site had been determined and will be announced later, semi-official news agency Tasnim reported.
"Investigations by the relevant agencies have accurately determined the cause of the incident... at the Natanz nuclear complex," spokesman Keyvan Khosravi said, according to Tasnim. "Due to security considerations, the cause and manner of the incident will be announced at a convenient time."
Iran's Atomic Energy Organisation initially reported an "incident" had occurred early on Thursday at Natanz. It later published a photo of a one-storey brick building with its roof and walls partly burned and a door hanging off its hinges. 
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