A building at Iran’s Natanz nuclear production plant, damaged in an explosion, July 2, 2020


Iran’s Supreme National Security Council is withholding its findings on the “main cause” of Thursday’s explosion at the Natanz nuclear facility.

Spokesman Keyvan Khosravi said on Friday, “Due to some security considerations, the cause and manner of this incident will be announced at a proper time.”

He claimed that investigators did not find any nuclear material in the above-ground building, reportedly used for balancing uranium centrifuges.

An “informed Iranian security official” had said on Thursday that there was no evidence of sabotage.

ORIGINAL ENTRY, JULY 3: An explosion has damaged a building at Iran’s Natanz nuclear site, but was the blast an accident or sabotage?

The detonation and fire damaged a building at the complex, the Islamic Republic’s center for production of nuclear fuel. The Atomic Energy Organization of Iran released a photo, and spokesman Bahram Kavalkandi denied any disruption of operations:

However, there were no images from inside the complex, where Iran has been installing advanced uranium centrifuges.

The installation began last summer as part of Iran’s suspension of commitments under the 2015 nuclear deal, following the Trump Administration’s withdrawal and imposition of comprehensive sanctions.

Tehran has also broken the deal’s limit on stocks of 3.67% uranium and raised production to 4.5%. However, it has yet to announce a return to pre-2015 production of 20% uranium, which potentially can be further enriched to 90% plus for military use.


A previously-unknown group, “Panthers of the Homeland”, claimed responsibility for the blast. The faction said it has carried out a series of attacks on regime targets.

The “Panthers” offered no evidence to support the claims.

But a “Middle Eastern intelligence official” declared that the explosion was caused by a device planted inside the facility. He asserted that much of the above-ground part of Natanz, where new centrifuges are balanced, was damaged.

An “informed Iranian security official” told State outlet Press TV that there was no evidence of sabotage.

From 2009, the US and Israel pursued cyber-attacks to disrupt the centrifuges. Officials claimed that the operations altered the computer code of Iran’s industrial equipment and destroyed about 1,000 centrifuges, setting back the nuclear program for more than a year.

Last week, there was an explosion at the Parchin military site, which Western intelligence agencies have claimed was connected to Iran’s military nuclear program in the early 2000s.

Days later the International Atomic Energy Agency adopted a resolution, over Tehran’s objections, for Iran to lift its barrier on access to two sites suspected of holding nuclear material more than 15 years ago.

See also Iran Daily, June 26: What Caused Explosion Near Military Base East of Tehran?
Iran Daily, June 6: IAEA — “Serious Concern” Over Tehran’s Denial of Access to Nuclear Sites

As the US seeks an extension of a UN arms embargo on Iran, Secretary of State Mike Pompeo told the Security Council on Tuesday:

Iran is also accumulating dangerous knowledge. Late last year, Iran announced that its scientists were working on a new centrifuge — the IR-9 — that would allow Tehran to enrich uranium up to 50 times faster than the IR-1 centrifuges allowed [under the 2015 nuclear deal].

The Atomic Energy Organization’s Kamalvandi said experts were investigating the cause of the explosion: “Since our main enrichment work is not done here, we will face no problem and no work stoppage or slowdown.”