Jerusalem
(CNN)Israel's army chief has appeared to hint at possible Israeli involvement in an incident at the Natanz nuclear site in Iran -- an event labeled a "terrorist action" by the head of Iran's atomic energy agency. Iranian officials on Sunday confirmed an "incident" at Natanz, an underground facility where uranium enrichment takes place. "Fortunately, the incident did not cause any human injuries or leaks," said Behrouz Kamalvand, a spokesman for Iran's Atomic Energy Organization (AEOI). "The causes of the accident are under investigation and further information will be announced later."
AEOI condemned the incident, calling it a "terrorist action," according to the Iranian telegram channel of the Revolution Guard Corps, or IRGC, a branch of the Iranian Armed Forces.
Just hours after Iranian officials reported the incident, Israel's army chief Aviv Kochavi said the country's "operations throughout the Middle East are not hidden from the eyes of the enemies."
"They are watching us, seeing the capabilities and carefully considering their steps," he said, speaking Sunday at a remembrance event in Jerusalem to mark fallen soldiers.
Reports in several Israeli media outlets Sunday quoted intelligence officials saying Israel's national intelligence agency, Mossad, was responsible for the incident. While few details of the unnamed officials are offered, some outlets described them as "Western intelligence sources," though it is not immediately clear whether "Western" includes the possibility the sources are from Israel or not.
Israel's Prime Minister's office offered no comment on the reports, but Prime Minister Benjamin Netanyahu addressed Iran Sunday at a toast to mark the anniversary of the founding of the state of Israel.
"The struggle against Iran and its proxies and the Iranian armament efforts is a huge mission," he said, appearing alongside Israel Defense Forces chief Kochavi and his senior commanders, as well as Defense Minister Benny Gantz. "The situation that exists today will not necessarily be the situation that will exist tomorrow."
Netanyahu is due to meet Monday with US Defense Secretary Lloyd Austin who is on a visit to the country. It is the highest-level visit to Israel by a member of the Biden administration and comes days after talks in Vienna aimed at restarting negotiations on a possible new nuclear deal between Iran and a US-led group of world powers.
US officials were also in Vienna and met with representatives from global powers who are still party to the deal. They did not meet with Iranian officials directly.
Former US President Donald Trump began imposing new sanctions on Iran as he withdrew the United States from the deal. Iranian officials have maintained the US must lift all Trump-era sanctions and return to the nuclear deal before it again complies with the agreement.
Israel's leader repeated his strong opposition this week to the prospect of a restored Joint Comprehensive Plan of Action (JCPOA)-type deal, saying Israel "would not be bound by any agreement that paves the way for Iran to develop nuclear weapons."
Iran condemns 'terrorist action'
Leaders in Iran condemned the incident.
Akbar Salehi, chief of Iran's Atomic Energy Organization, said: "Iran reserves the right to respond against the perpetrators, and those who committed the terrorist action," IRGC reported.
"Today's attack demonstrates that the enemies of Iran's progress and advancement in nuclear science, as well as nuclear negotiations, are in desperation committing terrorist actions against the nuclear technology at Natanz [nuclear facility]."
In Iranian news agency reports, other Iranian officials suggested the facility may have come under attack, speculating the plant may have been targeted as the country discusses a revival of the Iran nuclear deal with its Western signatories.
Malek Shariati Niaser, a member of Iran's Parliament, said: "The blackout in Natanz on the anniversary of National Nuclear Day is suspicious and may be due to sabotage while Iran is trying to convince the Western countries to lift the sanctions," the semi-official news website Entekhab.ir reported.
A spokesman for the International Atomic Energy Agency told CNN by email on Sunday the agency was aware of the media reports.
"We have no comment at this stage," he said.
During the 15th anniversary of Iran's National Nuclear Technology Day Saturday, Iranian President Hassan Rouhani announced new uranium enrichment centrifuges at the plant, stating that while Iran's nuclear activities are for "peaceful and civil purposes," the country's nuclear capability was also stronger than at any time before.
"Today, a chain of 164 IR-6 centrifuges was launched," Rouhani said Saturday, according to state-run Press TV. "It can provide us with products 10 times more than the former chain."
The Natanz nuclear plant lost a building when a fire broke out last July. The Iranian government said at the time that it was an attack on its nuclear program. It was also the target of the Stuxnet cyberattack in 2010, which security experts believe was carried out by Israel and the US.
