TEL AVIV, Israel — Israel’s military said Saturday it struck an Iranian nuclear research facility overnight and killed three senior Iranian commanders in targeted attacks, while emphasizing it was preparing for the possibility that the war could turn into a lengthy campaign.

Early Saturday, smoke could be seen rising from an area near a mountain in Isfahan, where a local official said Israel had attacked the nuclear research facility in two waves.

The target was two centrifuge production sites, and the attacks came on top of strikes on other centrifuge production sites elsewhere in recent days, according to an Israeli military official speaking on condition of anonymity under army guidelines to brief reporters. It was the second attack on Isfahan, which was hit in the first 24 hours of the war as part of Israel’s goal to destroy the Iranian nuclear program.

Akbar Salehi, Isfahan province’s deputy governor for security affairs, confirmed the Israeli strikes had caused damage to the facility but said there had been no human casualties.

Iran launched a new wave of drones and missiles at Israel but there were no immediate reports of significant damage, and the Israeli official called it a “small barrage” that was largely intercepted by Israel’s defenses.

The official said part of the reason that Iran’s overnight attack had been relatively small was that the military had been targeting its launchers, and estimates it has now taken out more than 50% of them.

“We’ve been able to take out a large amount of their launchers, creating a bottleneck – we’re making it harder for them to fire toward Israel,” he said. “Having said all that, I want to say the Iranian regime obviously still has capabilities.”

Israel’s Magen David Adom rescue service said Saturday an Iranian drone hit a two-story building in northern Israel, but there were no casualties.

Later, the Israeli military’s chief spokesman, Brig. Gen. Effie Defrin, said the army had been told by Chief of Staff Lt. Gen. Eyal Zamir to be prepared for a “prolonged campaign” to destroy its targets, including nuclear sites, enrichment facilities and missile infrastructure.

“We are deepening our strikes night after night and we have amazing achievements,” he said. “We will continue until the threat is removed.”

Talks in Switzerland fail to produce a breakthrough

Talks in Geneva on Friday failed to produce a breakthrough. European officials expressed hope for future discussions, and Iranian Foreign Minister Abbas Araghchi said he was open to further dialogue while emphasizing that Tehran had no interest in negotiating with the U.S. while Israel continued attacking.

“Iran is ready to consider diplomacy once again and once aggression is stopped and the aggressor is held accountable for the crimes committed,” he told reporters.

No date was set for the next round of talks.

Iran warns against US military involvement

U.S. President Donald Trump is weighing active U.S. military involvement in the conflict, which Araghchi said Saturday “would be very unfortunate.”

“I think that it would be very, very dangerous for everyone,” he said in Istanbul, speaking on the sidelines of a meeting of the Organization of Islamic Cooperation.

The war between Israel and Iran erupted June 13, with Israeli airstrikes targeting nuclear and military sites, top generals and nuclear scientists. At least 657 people, including 263 civilians, have been killed in Iran and more than 2,000 wounded, according to a Washington-based Iranian human rights group.

Iran has retaliated by firing more than 450 missiles and 1,000 drones at Israel, according to Israeli army estimates. Most have been shot down by Israel’s multitiered air defenses, but at least 24 people in Israel have been killed and hundreds wounded.

Israeli Prime Minister Benjamin Netanyahu has said Israel’s military operation in Iran would continue “for as long as it takes” to eliminate what he called the existential threat of Iran’s nuclear program and arsenal of ballistic missiles.

But Netanyahu’s goal could be out of reach without U.S. help. Barring a commando raid or even a nuclear strike, Iran’s underground Fordo uranium enrichment facility is considered to be out of reach to all but America’s “bunker-buster” bombs. Trump said he would put off deciding whether to join Israel’s air campaign against Iran for up to two weeks.

Israel continues targeted attacks on Iranian military commanders

In Israel’s opening attack, it killed three of Iran’s top military leaders: one who oversaw the entire armed forces, Gen. Mohammad Bagheri; one who led the paramilitary Revolutionary Guard, Gen. Hossein Salami; and the head of the Guard’s ballistic missile program, Gen. Amir Ali Hajizadeh.

The targeted killings of senior commanders continued, with Israel’s defense minister saying Saturday that the military had killed a commander in Iran’s paramilitary Revolutionary Guard who financed and armed Hamas in preparation for the Oct. 7, 2023, attack on Israel that sparked the 20-month long war in Gaza.

Israel said Saeed Izadi was commander of the Palestine Corps for the Iranian Quds Force, an elite arm of the Guard that conducts military and intelligence operations outside Iran, and that he was killed in an apartment in the city of Qom.

Iranian officials did not immediately confirm the death, but the Qom governor’s office did say there had been an attack on a four-story apartment building and local media reported two people had been killed.

Israel also said it had killed the commander of the Quds Force’s weapons transfer unit, who it said was responsible for providing weapons to Hezbollah and Hamas. Behnam Shahriyari was killed in his car while traveling in western Iran, the military said.

A commander of Iran’s drone force was also killed overnight, the Israeli official who briefed reporters said.

Iran threatens head of U.N. nuclear watchdog

On Friday, the head of the U.N. nuclear watchdog warned at an emergency meeting of the U.N. Security Council against attacks on Iran’s nuclear reactors, particularly its only commercial nuclear power plant in the southern city of Bushehr.

“I want to make it absolutely and completely clear: In case of an attack on the Bushehr nuclear power plant, a direct hit would result in a very high release of radioactivity to the environment,” said Rafael Grossi, head of the International Atomic Energy Agency. “This is the nuclear site in Iran where the consequences could be most serious.”

Israel has not targeted Iran’s nuclear reactors, instead focusing its strikes on the main uranium enrichment facility at Natanz, centrifuge workshops near Tehran, laboratories in Isfahan and the country’s Arak heavy water reactor southwest of the capital.

Iran previously agreed to limit its uranium enrichment and allow international inspectors access to its nuclear sites under a 2015 deal with the U.S., France, China, Russia, Britain and Germany in exchange for sanctions relief. But after Trump pulled the U.S. unilaterally out of the deal during his first term, Iran began enriching uranium up to 60% – a short, technical step away from weapons-grade levels of 90% – and restricting access to its nuclear facilities.

Iran has long maintained its nuclear program is for peaceful purposes, but it is the only non-nuclear-weapon state to enrich uranium up to 60%. Israel is widely believed to be the only Middle Eastern country with a nuclear weapons program but has never acknowledged it.

Leaders in Iran have blamed Grossi’s statements about the status of Iran’s nuclear program for prompting Israel’s attack.

On Saturday, a senior adviser for Iran’s Supreme Leader Ali Khamanei, Ali Larijani, said in a brief social media post without elaboration that Iran would make Grossi “pay” once the war with Israel is over.

Rising reported from Dubai, United Arab Emirates. Associated Press writers Mehmet Guzel in Istanbul, Josef Federman in Jerusalem and Farnoush Amiri in Dubai, UAE contributed to this report.