There were no immediate reports of casualties.

In a recorded message to the nation broadcast as Iranian missiles flew toward Israel, Ayatollah Ali Khamenei said the military was prepared to counterattack. “Don’t think that they (Israel) hit and it’s over. No. They started the work and started the war. We will not allow them to escape safely from this great crime they committed,” he said.

The US began shifting military resources in the region, including ships, as Israel prepared for more retaliation, two US officials said.

Countries in the region condemned Israel’s attack, while leaders around the globe called for immediate deescalation from both sides.

Israel’s military said about 200 aircraft were involved in the initial attack on about 100 targets. Its Mossad spy agency positioned explosive drones and precision weapons inside Iran ahead of time, and used them to target Iranian air defenses and missile launchers near Tehran, according to two security officials who spoke on condition of anonymity.

Among the key sites Israel attacked was Iran’s main nuclear enrichment facility in Natanz, where black smoke could be seen rising into the air. It also appeared to strike a second, smaller nuclear enrichment facility in Fordo, about 100 km southwest of Tehran, according to an Iranian news outlet close to the government that reported hearing explosions nearby.

Israel said it struck a nuclear research facility in Isfahan, too, though Iran didn’t immediately acknowledge it. Israel said it destroyed dozens of radar installations and surface-to-air missile launchers in western Iran.

Israel military spokesman Brig. Gen. Effie Defrin said the Natanz facility was “significantly damaged” and that the operation was “still in the beginning”.

The first wave of strikes had given Israel “significant freedom of movement” in Iran’s skies, clearing the way for further attacks, according to an Israeli military official who said Israel is prepared for an operation that could last up to two weeks, but that there was no firm timeline and it would depend largely on how Iran responds.

Among those killed were 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 programme, Gen. Amir Ali Hajizadeh. Iran confirmed all three deaths, significant blows to its governing theocracy that will complicate efforts to retaliate. Khamenei said other top military officials and scientists were also killed.

Israeli Prime Minister Benjamin Netanyahu said the attack had been months in the making. In a video statement sent to journalists Friday, Netanyahu said he ordered plans for the attack last November, soon after the killing of Hassan Nasrallah, the leader of Hezbollah in Lebanon, one of Iran’s strongest proxies. Netanyahu said the attack was planned for April but was postponed.

In its first response, Iran fired more than 100 drones at Israel which said the drones were being intercepted outside its airspace, and it was not immediately clear whether any got through.

Israel’s military said it called up reservists and began stationing troops in “all combat arenas” throughout the country as it braced for further retaliation from Iran or Iranian proxy groups on its border.

US President Donald Trump urged Iran to reach a deal with the US on its nuclear programme, warning on his Truth Social platform that Israel’s attacks “will only get worse”.

“Iran must make a deal, before there is nothing left, and save what was once known as the Iranian Empire,” he wrote. Earlier in the week, officials in Washington had cautioned Israel against an attack so as not to disrupt US negotiations with Iran over its nuclear enrichment programme. On Friday, they stressed the US had not been involved in the attack, and warned against any retaliation targeting US interests or personnel.

Israeli leaders cast the attack as necessary to head off an imminent threat that Iran would build nuclear bombs, though it remains unclear how close the country is to achieving that or whether Iran had actually been planning a strike. Iran maintains its nuclear programme is for civilian purposes only.

For Netanyahu, the operation distracts attention from Israel’s ongoing and increasingly devastating war in Gaza, which is now over 20 months old. There is a broad consensus in the Israeli public that Iran is a major threat, and Israel’s opposition leader, Yair Lapid, a staunch critic of Netanyahu, offered his “full support” for the mission against Iran. But if Iranian reprisals cause heavy Israeli casualties or major disruptions to daily life, public opinion could shift quickly.

The Iran-backed Lebanese militant group Hezbollah issued a statement that offered condolences and condemned the attack, but did not threaten to join Iran in its retaliation. Hezbollah’s latest war with Israel, which killed much of the group’s senior leadership, ended with a US-brokered ceasefire in November.

Khamenei, the Iranian Supreme Leader, said in a statement that Israel “opened its wicked and blood-stained hand to a crime in our beloved country, revealing its malicious nature more than ever by striking residential centres”.

Netanyahu expressed hope the attacks would trigger the downfall of Iran’s theocracy, saying his message to the Iranian people was that the fight was not with them, but with the “brutal dictatorship that has oppressed you for 46 years”.“I believe that the day of your liberation is near,” he said.

US Secretary of State Marco Rubio said Israel took “unilateral action against Iran” and that it believed the strikes were necessary for its self-defence.

The International Atomic Energy Agency confirmed Iran’s uranium enrichment facility at Natanz was hit, and said it was closely monitoring radiation levels.