Iran’s Natanz nuclear site faced an unprecedented electrical outage on Sunday just as it started up a new program to more quickly enrich uranium, according to the Associated Press, citing Iran state television. Most of the power in the above ground workshops and underground enrichment halls suddenly went off, according to civilian nuclear program spokesman Behrouz Kamalvandi. “Here the power has been cut off indeed, and we do not know the reason for the outage,” he said. “The incident is under investigation and we will inform you about the reason as we find out.” Malek Shariati Niasar, spokesman for the Iranian parliament’s energy committee, called the incident “very suspicious,” and raised concerns about potential “sabotage and infiltration” in a tweet Sunday morning. The Vienna-based International Atomic Energy Agency said it was “aware of the media reports,” but declined to comment.