A power failure at Iran's Natanz uranium enrichment facility on Sunday was caused by a large explosion, in what appears to be Israeli sabotage, that could set back production at the site by at least nine months, The New York Times reported the same day.

The report quoted intelligence officials as saying the explosion completely destroyed the independent internal power system that supplies the underground centrifuges that enrich uranium.

The inside of Iran's Natanz nuclear facility shown to the Iranian media in May 2019. (Photo courtesy of the Atomic Energy Organization of Iran)(Kyodo)

The officials, who spoke on the condition of anonymity to describe a classified Israeli operation, said that the explosion had dealt a severe blow to Iran's ability to enrich uranium and that it could take at least nine months to restore Natanz's production.

Israeli media had initially reported the incident was caused by a cyberattack.

Ali Akbar Salehi, the head of the Atomic Energy Organization of Iran, on Sunday called the incident an act of "nuclear terrorism," while a Foreign Ministry spokesman on Monday acknowledged that centrifuges used for enrichment were damaged.

Iran "reserves the right to take action against masterminds, perpetrators and conspirators of this act," Salehi was quoted as saying by semiofficial Tasnim News Agency.

His remarks were echoed by Foreign Ministry spokesman Saeed Khatibzadeh, who said, "Iran's response will be taking revenge on the Zionist regime in due time and place," according to Tasnim.

Iranian state media earlier reported that no injuries or contamination resulted from the incident.

Another mysterious explosion occurred at the Natanz facility in July last year, damaging the building developing and assembling centrifuges used for uranium enrichment. Iran has said it was sabotage involving Israel.

The same facility was targeted over a decade ago by the Stuxnet computer virus believed to have been jointly developed by the United States and Israel.

Iran had just announced on Saturday that it had started up advanced IR-6 uranium enrichment centrifuges at Natanz, in a breach of its undertakings under the 2015 nuclear deal with world powers.

The agreement stipulates that Iran can only use first-generation IR-1 centrifuges for enrichment.


Related coverage:

Iran's Natanz nuclear facility suffers electrical system "accident"

Iran proposes "endgame scheme" to revive nuclear deal

Iran, partners discuss "new ideas" in Germany to revive nuclear deal