Iranian officials have said a fire at the country’s Natanz nuclear facility late last week may have been caused by a cyber-attack.
Network-based attacks on critical infrastructure have become a growing concern, with the UK’s National Cyber Security Centre (NCSC) issuing warnings around the threat.
Iran’s Natanz uranium-enrichment site is one of several monitored by the UN’s nuclear regulator, the International Atomic Energy Agency (IAEA).
The Atomic Energy Organisation of Iran (AEOI) said the fire occured on Thursday at the plant, and published a photo of a one-storey brick building, which US intelligence analysts identified as a new centrifuge assembly workshop.
The AEOI said there had been no fatalities and there were no concerns about contamination.
Civil defence chief Gholamreza Jalali later said the incident may have been caused by cyber-sabotage and promised retaliation if this was the case.
“If it is proven that our country has been targeted by a cyber attack, we will respond,” Jalali told state television late on Thursday.
Three unnamed Iranian officials told Reuters they believed the fire had resulted from a cyber-attack, without citing evidence.
One of the officials said the attack had targeted a centrifuge assembly building, saying Iran’s enemies had carried out similar attacks in the past.
State news agency IRNA said in an article referred to “the crossing of red lines” by Israel and the United States, but did not directly accuse either country.
The IAEA said the incident was not expected to affect its monitoring activities at the site.
Natanz, located in the desert in the Isfahan province, is the centrepiece of Iran’s nuclear enrichment programme.
The country reduced its nuclear work in exchange for a removal of global sanctions in 2015, but has more recently begun increasing enrichment again as sanctions have returned.