Iran calls blackout at underground atomic facility 'nuclear terrorism.' Israeli outlets blame an Israeli cyberattack.

• Iran blames a Sunday blackout at a nuclear facility on "nuclear terrorism."
• The country hasn't assigned blame, but Israeli media has reported an Israeli cyberattack is responsible.
• The attack comes as US Defense Secretary Lloyd Austin is in Israel to meet Prime Minister Benjamin Netanyahu.

Ali Akbar Salehi, the head of Iran's Atomic Energy Organization, described a Sunday morning blackout at its Natanz uranium enrichment facility as an act of "nuclear terrorism." The country fell short of assigning blame for the blackout, which occurred while negotiations continue between Iran and US-aligned nations over reinstating the nuclear deal.

Multiple Israeli media outlets, including Haaretz, claimed that the blackout was caused by an Israeli cyberattack on the eve of Israel's independence day. On Sunday night, embattled Israeli Prime Minister Benjamin Netanyahu spoke to security chiefs, such as Mossad head, Yossi Cohen, asking them to "continue in this direction, and to continue to keep the sword of David in your hands."

If Israel is responsible, the act threatens to continue to heighten regional tensions between Iran and America's ally. Netanyahu also met with US Defense Secretary Lloyd Austin on Sunday along with his Dfeense Minister, Benny Gantz.

The blackout came hours after the facility began to operate new centrifuges that can enrich uranium more quickly.

Salehi did not expand on how the blackouts had affected the atomic facility but said that the country plans to "seriously improve" its nuclear technology while trying to also lift international sanctions. Nuclear spokesperson Behrouz Kamalvandi told Iranian state television that "there was no casualty or damage and there is no particular contamination or problem"

Iran's nuclear program has seen many previous acts of international sabotage. In July,the Natanz plant experienced a mysterious explosion, and in November, a leading Iranian nuclear scientist was killed by a remote-controlled machine gun. Iran blames Israel for both and is now building a new facility underground, which was targeted in Sunday's attack.

In 2010, the facility was attacked by the Stuxnet computer virus, destroying centrifuges at the Natanz plant. The virus is widely considered to be created by the US and Israel.

Israeli media reports, such as public broadcaster Kan, said that "experts" assume that Sunday's attack shut down much of the facility. The reports did not cite their sources for the information.

After the Trump administration withdrew from the Iran nuclear deal in 2018, Iran has stopped following formal limits on its uranium stockpile, now enriching up to 20% purity. This is still below the 90% purity needed to build weapons.

Iran has long maintained its nuclear program is for peaceful purposes.

Earlier this week, an Iranian cargo ship that was connected to the Iranian Revolutionary Guard off the coast of Yemen was hit by an explosion. Iran has blamed Israel for the blast, which occurred in a hot zone near the conflict between Saudi Arabian forces and the Iranian- aligned Houthis in Yemen. The Wall Street Journal reported that Israeli cover operations are responsible for over a dozen oil tanker attacks in recent years.