Iran says there has been an “incident” at one of its nuclear facilities monitored by the UN's atomic agency, but there was no damage to the site.
Iran’s Atomic Energy Organization spokesman Behruz Kamalvandi said the incident occurred early on July 2 at the Natanz nuclear enrichment facility in central Iran where a building under construction, described as an "industrial shed," was damaged, though there was no impact on its centrifuge facility.
There was no previously announced construction work at Natanz, the Islamic republic's main uranium enrichment center located some 250 kilometers south of Tehran, which includes underground facilities built under some 7.6 meters of concrete to offer protection from air strikes.
"The incident did not cause any casualties and did not damage the current activities of this complex," Kamalvandi was quoted as saying by several Iranian media outlets including the state-run IRNA news agency.
The affected building was above ground and not part of the enrichment facility itself, Kamalvandi said, adding that there was “no need for concern” over the incident, which was being investigated by experts from the organization.
In a statement sent to BBC Persian journalists prior to the announcement of the fire, an unknown group calling itself "Cheetahs of the Homeland" claimed it had attacked the facility, the British broadcaster reported.
It quoted the statement as saying members of the group were part of "underground opposition within Iran's security apparatus."
The authenticity of the claim could not immediately be verified.
Natanz is among the sites now monitored by the International Atomic Energy Agency (IAEA) after Iran's 2015 nuclear deal with world powers.
U.S. President Donald Trump unilaterally withdrew from the deal in May 2018. Iran now is breaking all the production limits set by the deal, but still allows IAEA inspectors and cameras to watch its nuclear sites.
Currently, the IAEA says Iran enriches uranium to about 4.5 percent purity, above the terms of the nuclear deal, but far below weapons-grade levels of 90 percent.
Natanz was at the center of a dispute last year as Iranian officials refused to allow an IAEA inspector into the facility in October after allegedly testing positive for suspected traces of explosive nitrates.