JERUSALEM — The Iranian foreign minister, Mohammad Javad Zarif, vowed revenge against Israel on Monday morning, a day after a blackout at an Iranian nuclear enrichment site was attributed to an Israeli attack.
Mr. Zarif’s comments highlight the risk of escalation in a yearslong shadow war between Iran and Israel. They also threaten to overshadow efforts in Vienna to encourage Iran to reimpose limits on its nuclear program in exchange for the lifting of American sanctions.
In a statement broadcast by Iranian state television, Mr. Zarif was quoted as saying: “The Zionists want to take revenge because of our progress in the way to lift sanctions.”
He added, “But we will take our revenge from the Zionists,” according to the broadcast.
Mr. Zarif’s reported comments followed a power failure on Sunday at the Natanz uranium enrichment site that Iranian officials attributed to Israeli sabotage. The Israeli government formally declined to comment on its involvement, but American and Israeli officials confirmed separately to The New York Times that Israel had played a role. Several Israeli news outlets, citing intelligence sources, attributed the attack to the Mossad, the Israeli spy agency.
Two officials briefed on the matter told The Times that the blackout was caused by an explosion that targeted the power supply for thousands of underground centrifuges that form the main Iranian enrichment program.
The U.S. defense secretary, Lloyd J. Austin III, was expected to discuss the incident in meetings in Israel on Monday with his Israeli counterpart, Benny Gantz, and the Israeli prime minister, Benjamin Netanyahu. It was unclear whether the Israeli government had given the United States advance warning of any operation.
Iran has long maintained that its nuclear program is peaceful and aimed at energy development. But Israel sees it as an existential threat, since Iranian leaders have often called for Israel’s destruction.
The events of Sunday could complicate efforts by the Biden administration to encourage Iran to return to something close to a 2015 agreement negotiated by the Obama administration, in which Tehran promised to limit its enrichment program.
The deal collapsed in 2018, when President Donald J. Trump reimposed sanctions on Iran, and Iran reneged on commitments to curb its nuclear plans.
Israel opposes returning to the same deal, arguing that it did not impose strong enough or long enough restrictions on Iranian nuclear activity. Analysts were divided about whether Israel’s aggression was intended to scupper the negotiations altogether — or to simply weaken Iran’s hand at the table.
For years, Israel and Iran have been engaged in a low-level shadow conflict.
Both have been accused of cyberattacks on the other’s territory. Iran finances and arms militias hostile to Israel across the Middle East, and has been accused of attempted assassinations of Israeli diplomats across the world. Israel is believed to be responsible for the assassination of several Iranian nuclear scientists, most recently in November, when a leading architect of the Iranian nuclear program was killed in an ambush.
Those attacks have escalated at sea in the past two years, as Israel began to attack ships carrying Iranian fuel, and Iran seemed to respond by targeting at least two Israeli-owned cargo ships.
Both sides managed to contain the conflict, partly by refraining from speaking too publicly about the attacks.
But the public assertion of Israeli involvement in Sunday’s episode raised fears that Iran would seek to save face by mounting a stronger military response than usual.
“Once Israeli officials are quoted, it requires the Iranians to take revenge,” Danny Yatom, a former head of the Mossad, said in an interview Monday with a radio station run by the Israeli Army. “There are actions that must remain in the dark,” he added.
But others expressed the feeling that Iran would be unwilling to escalate further while there was still a chance that the United States might pare back sanctions on the Iranian economy in exchange for Iran’s scaling back its nuclear program.
Chuck Freilich, a former deputy national security adviser in Israel, said: “I don’t think the Iranians want a major confrontation at this point — I think they want a deal. And that doesn’t need a confrontation.”
In Israel, some also questioned whether the attack served a domestic purpose for Mr. Netanyahu.
The Israeli prime minister is standing trial for corruption and is struggling to form a new coalition government after a general election last month that gave no party an overall majority. Some analysts say they believe that a very public confrontation with Iran might help Mr. Netanyahu persuade wavering coalition partners that now is not the time to bring down an experienced prime minister.
“He may want to both build up his image and create a little bit of a foreign policy crisis, which then helps him solve the coalition crisis,” Mr. Freilich said.
Myra Noveck contributed reporting.
