Iran has launched dozens of aerial drones and missiles at Israel, marking a widely anticipated reprisal attack.
It is the first such direct clash between the two enemies, who have been engaged in a years-long shadow war, with Iran using proxy forces.
The Israeli military said Israel and other countries had intercepted hundreds of cruise missiles and drones, mostly outside Israeli airspace.
US President Joe Biden said “we helped Israel take down nearly all” of them.
“Iran and its proxies operating out of Yemen, Syria and Iraq launched an unprecedented air attack against military facilities in Israel,” he said, expressing strong condemnation.
Iran’s Islamic Revolution Guard Corps (IRGC) said the attack was aimed at “specific targets”.
Iran had vowed to retaliate for a strike on its consulate in Syria on 1 April which killed seven IRGC officers, including a top commander. It accused Israel of carrying out that attack, but Israel neither confirmed nor denied it.
Israel’s Prime Minister Benjamin Netanyahu called a war cabinet meeting after the start of the Iranian attack, and later spoke to President Biden, who said he had reaffirmed “America’s ironclad commitment to the security of Israel”.
Israel Defense Forces (IDF) spokesman Rear Admiral Daniel Hagari said some Iranian missiles had hit inside Israel, causing minor damage to a military base but no casualties.
Israel’s ambulance service said a seven-year-old Bedouin girl had been injured by shrapnel from falling debris in the southern Arad region.
“Tonight’s wide-scale attack by Iran is a major escalation,” Mr Hagari said. “Together with our allies and partners, we are operating at full force to defend the State of Israel and the people of Israel.”
In a separate briefing, he said Iran had fired more than 300 projectiles at Israel overnight, 99% of which were shot down. He added that some of the launches came from Iraq and Yemen.
Two US officials told CBS, the BBC’s US partner, that American forces had shot down several drones, but did not specify where or how they were intercepted.
The UK Ministry of Defence said RAF jets had been deployed in Iraq and Syria to intercept “any airborne attacks within range of our existing missions”.
Sirens sounded across Israel and loud explosions were heard over Jerusalem, with air defence systems shooting down objects over the city.
Israel, Lebanon and Iraq closed their airspaces, and Syria and Jordan put their air defences on alert.
Iran’s IRGC – the most powerful branch of its armed forces – said it had launched the attack “in retaliation against the Zionist regime’s [Israel] repeated crimes, including the attack on the Iranian embassy’s consulate in Damascus”.
Shortly before news of Iran’s launches, Prime Minister Netanyahu said Israel’s “defensive systems” were deployed.
“We are ready for any scenario, both defensively and offensively. The State of Israel is strong. The IDF is strong. The public is strong.
“We appreciate the US standing alongside Israel, as well as the support of Britain, France and many other countries.”
President Biden had cut short a trip to Delaware to return to the White House as tensions mounted on Saturday.
After speaking to Mr Netanyahu later he said “tomorrow I will convene my fellow G7 leaders to co-ordinate a united diplomatic response to Iran’s brazen attack”.
UK Prime Minister Rishi Sunak condemned Iran’s “reckless” attack, vowing that the UK would “continue to stand up for Israel’s security and that of all our regional partners”.
UN Secretary General António Guterres issued a statement saying he “strongly condemn[ed] the serious escalation represented by the large-scale attack launched on Israel” by Iran.
He said he was calling for “an immediate cessation of these hostilities” and for all sides to exercise maximum restraint.
“Neither the region nor the world can afford another war,” he warned.
The UN Security Council will convene on Sunday for an emergency meeting over Iran’s attack on Israel, its president Vanessa Frazier said.
Earlier this week, Israel’s defence and foreign ministers warned that if Iran attacked Israel, Israel would strike back inside Iran.
Additional reporting: Laurence Peter and Emily Atkinson