Iran will retaliate against any country that carries out cyber attacks on its nuclear sites, the head of civilian defence said, after a fire at its Natanz plant which some Iranian officials said may have been caused by cyber sabotage.
The Natanz uranium-enrichment site, much of which is underground, is one of several Iranian facilities monitored by inspectors of the International Atomic Energy Agency (IAEA), the UN nuclear watchdog.
Iran's top security body said on Friday the cause of the "incident" at the nuclear site had been determined, but "due to security considerations" it would be announced at a convenient time.
Iran's Atomic Energy Organisation initially reported an "incident" had occurred early on Thursday at Natanz, located in the desert in the central province of Isfahan.
It later published a photo of a one-storey brick building with its roof and walls partly burned. A door hanging off its hinges suggested there had been an explosion inside the building.
"Responding to cyber attacks is part of the country's defence might. If it is proven that our country has been targeted by a cyber attack, we will respond," civil defence chief Gholamreza Jalali told state TV late on Thursday.
An article issued on Thursday by state news agency IRNA addressed what it called the possibility of sabotage by enemies such as Israel and the United States, although it stopped short of accusing either directly.