Iran’s Natanz nuclear facility south of Tehran, suffered a problem Sunday involving its electrical distribution grid. The incident happened just hours after the facility’s new advanced centrifuges, which can more quickly enrich uranium, came online. At first, Iranian state TV reported the incident as an accident but later changed the narrative and called it a sabotage.

Power was cut to the above-ground workshops and underground enrichment halls, civilian nuclear program spokesman Behrouz Kamalvandi told Iranian state television.

Ali Akbar Salehi, one of Iran’s top nuclear officials, did not say who was to blame for the “terrorist act”, which caused the power failure.

Yet, many news media sites are saying that it was the work of the Israeli Mossad spy agency.