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. 

Salehi urged the International Atomic Energy Agency to deal with, what he called, nuclear terrorism.

This is the latest incident impacting one of Tehran’s most secure sites; it comes amid negotiations over the renewal of the Joint Comprehensive Plan of Action (JCPOA).

Despite the renewed negotiations between Iran and the other JCPOA signatories in Vienna, the Iranians not only conducted another breach of the nuclear agreement on Saturday but advertised it on state-run television: Under the JCPOA, Iran is allowed to produce and store limited qualities of enriched uranium, which is to be used for the production of fuel for commercial power plants. However, the Iranians have been enriching uranium one step below weapons-grade.

Iran’s President Hassan Rouhani was filmed live over the weekend as he inaugurated new centrifuges at the Natanz site in a ceremony. The story carried the news that the new improved centrifuges were enriching uranium.

Iranian Foreign Minister Mohammad Javad Zarif has blamed the Israelis for the incident on Natanz. He warned that Iran would take revenge, according to the Iranian IRNA news. 

“The political and military officials of the Zionist regime had explicitly stated that they would not allow progress in lifting the oppressive sanctions and now they think that they will achieve their goal, but the Zionists will get their answer in further nuclear progress,” said Zarif. 

“Natanz will be stronger than ever with more advanced machines, and if they think our hand in negotiation is weak, this act will strengthen our position in the negotiations.”

Meanwhile, Israel Defense Forces (IDF) Chief of Staff LTG Aviv Kohavi hinted that Israel may have been involved.

“The IDF’s actions throughout the Middle East are not hidden from our enemies’ vision, who are observing us, seeing our capabilities, and carefully considering their next steps,” he said at an event honoring fallen troops on Independence Day. 

“By virtue of clever operational activities, the past year was one of the most secure years that the citizens of the State of Israel have known,” Kohavi added. “We will continue to act, combining power and discretion, determination and responsibility – all of this to guarantee the security of the State of Israel.”

Prime Minister Benjamin Netanyahu also hinted that Israel’s Mossad may have been behind the incident. He commented at an Independence Day event that “The situation that exists today will not necessarily be the situation that will exist tomorrow.”

Israel and the U.S. were reportedly behind the Stuxnet Virus in 2010 which hit Natanz with a cyberattack that destroyed 1,000 centrifuges. Further, last July, an explosion and massive fire hit the central centrifuge workshop. 

Iranian MP Ali Haddad blamed the Israelis for this as well as other incidents. “Yesterday the assassination of a nuclear scientist and today the attack on the Iranian ship Saviz and the sabotage of the Natanz nuclear facility,” Haddad tweeted.

While the Iranians have not attached any blame to other Gulf countries for the incident at Natanz, tensions are running high. This is especially true in Saudi Arabia, where many Saudis are saying the West, especially the U.S., isn’t putting enough pressure on Iran in the re-negotiations on the JCPOA.