TEL AVIV, Israel — Israel’s military announced on Saturday that it launched an attack on an Iranian nuclear research facility overnight, resulting in the deaths of three high-ranking Iranian commanders. The military also emphasized its readiness for a potentially prolonged conflict.

The risk of a broader conflict loomed as well. Iranian-supported Houthi rebels in Yemen declared their intent to resume assaults on U.S. ships and warships in the Red Sea if the Trump administration decides to support Israel’s military actions against Iran. The Houthis had previously halted these attacks in May following an agreement with the administration.

In Iran, smoke was seen rising near a mountainous area in Isfahan. According to Akbar Salehi, the province’s deputy governor for security affairs, the Israeli strikes damaged the facility but did not result in any casualties.

The target was two centrifuge production sites, 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 Iran’s nuclear program.

The International Atomic Energy Agency confirmed the latest attack.

Iran launched a new wave of drones and missiles at Israel but there were no immediate reports of significant damage. The Magen David Adom rescue service said a drone hit a two-story building in northern Israel, with no casualties.

The Israeli official called it a “small barrage” that was largely intercepted by Israel’s defenses. The official estimated that Israel’s military has taken out more than 50% of Iran’s launchers.

“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.”

The Israeli military’s chief spokesman, Brig. Gen. Effie Defrin, later said Chief of Staff Lt. Gen. Eyal Zamir told the army to be prepared for a “prolonged campaign.”

U.S. President Donald Trump is weighing active U.S. military involvement in the war. On Saturday, Iranian Foreign Minister Abbas Araghchi said “I think that it would be very, very dangerous for everyone.” He spoke on the sidelines of an Organization of Islamic Cooperation meeting in Turkey.

Barring a commando raid or even a nuclear strike, Iran’s underground Fordo uranium enrichment facility is considered out of reach to all but America’s “bunker-buster” bombs. Trump said he would put off his decision on military involvement for up to two weeks.

The war erupted June 13, with Israeli airstrikes targeting Iran’s nuclear and military sites, top generals and nuclear scientists. At least 722 people, including 285 civilians, have been killed in Iran and more than 2,500 wounded, according to a Washington-based Iranian human rights group.

One Tehran resident, Nasrin, writhed in her hospital bed as she described how a blast threw her against a wall in her apartment. “I’ve had five surgeries. I think I have nothing right here that is intact,” she said Saturday. Another resident, Shahram Nourmohammadi, said he had been making deliveries when “something blew up right in front of me” at an intersection.

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

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% — a short, technical step away from weapons-grade levels of 90%. Israel is widely believed to be the only Middle Eastern country with a nuclear weapons program but has never acknowledged it.

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

Talks in Geneva on Friday failed to produce a breakthrough. European officials expressed hope for future discussions. Iran’s foreign minister said he was open to further dialogue while emphasizing that Tehran had no interest in negotiating with the U.S. while Israel continues to attack.

“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 a new round of talks.

For many Iranians, updates remained difficult. Internet-access advocacy group NetBlocks.org said Saturday that limited internet access had again “collapsed.” A nationwide internet shutdown has been in place for several days.

Israel’s opening attack killed three of Iran’s top military leaders: one who oversaw the 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.

Israel’s defense minister said Saturday the military has killed a Revolutionary Guard commander who financed and armed Hamas in preparation for the Oct. 7, 2023, attack on Israel that sparked the ongoing 20-month war in Gaza.

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

Israel also said it 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 while traveling in western Iran, the military said.

Iranian leaders say IAEA chief Rafael Grossi’s statements about the status of Iran’s nuclear program have prompted Israel’s attack.

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

Grossi, the head of the U.N. nuclear watchdog, warned Friday 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.

“In case of an attack on the Bushehr nuclear power plant, a direct hit would result in a very high release of radioactivity,” Grossi said, adding: “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 in exchange for sanctions relief. But after Trump pulled the U.S. out of the deal during his first term, Iran began enriching uranium up to 60% and restricting access to its nuclear facilities.

Iran has insisted on its right to enrich uranium — at lower levels — in recent talks over its nuclear program. But Trump, like Israel, has demanded Iran end its enrichment program altogether.

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

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