Washington said it would work with longtime ally Israel to make sure Iran faced "severe consequences" for Tuesday's attack, which Israel said involved more than 180 ballistic missiles.
The United Nations Security Council scheduled a meeting about the Middle East for Wednesday, and the European Union called for an immediate ceasefire.
Israelis took cover on the side of the road as sirens warned of incoming missiles fired from Iran. (AP PHOTO)
"Our action is concluded unless the Israeli regime decides to invite further retaliation. In that scenario, our response will be stronger and more powerful," Iranian Foreign Minister Abbas Araqchi said on X early on Wednesday.
Israel renewed its bombardment early on Wednesday of Beirut's southern suburbs, a stronghold of the Iran-backed armed Hezbollah group, with at least a dozen airstrikes against what it said were targets belonging the group.
Large plumes of smoke were seen rising from parts of the suburbs. Israel issued new evacuation orders for the area, which have largely emptied after days of heavy strikes.
Iran's attack marked it biggest ever military blow against Israel.
Sirens sounded across the country and explosions rattled Jerusalem and the Jordan River valley as the entire population was told to move into bomb shelters.
No injuries were reported in Israel, but one man was killed in the occupied West Bank, authorities there said.
This morning, — President Biden (@POTUS) @VP and I convened our national security team to discuss Iranian plans to launch an imminent missile attack against Israel.We discussed how the United States is prepared to help Israel defend against these attacks, and protect American personnel in the region.October 1, 2024
Iran described the campaign as defensive and solely aimed at Israeli military facilities. Iran's state news agency said three Israeli military bases had been targeted.
Tehran said its assault was a response to Israeli killings of militant leaders and aggression in Lebanon against Hezbollah and in Gaza.
Israel activated air defences against Iran's bombardment and most missiles were intercepted "by Israel and a defensive coalition led by the United States," Israeli Rear Admiral Daniel Hagari said in a video on X, adding: "Iran's attack is a severe and dangerous escalation."
Israeli Prime Minister Benjamin Netanyahu vowed to hit back.
"Iran made a big mistake tonight - and it will pay for it," he said at the outset of an emergency political security cabinet meeting late on Tuesday, according to a statement.
Prime Minister Benjamin Netanyahu at the Start of the Security Cabinet Meeting: — Prime Minister of Israel (@IsraeliPM) "This evening, Iran made a big mistake – and it will pay for it." pic.twitter.com/D7XYpDmiuJOctober 1, 2024
Iran's General Staff of the Armed Forces said in a statement carried by state media that any Israeli response would be met with "vast destruction" of Israeli infrastructure. It also said it would target regional assets of any Israeli ally that got involved.
Fears that Iran and the US could be drawn into a regional war have risen with Israel's growing assault on Lebanon in the past two weeks, including the start of a ground operation there on Monday, and its year-old conflict in the Gaza Strip.
Iran's forces on Tuesday used hypersonic Fattah missiles for the first time, and 90 per cent of its missiles successfully hit their targets in Israel, the Revolutionary Guards said.
US President Joe Biden expressed full US support for Israel and described Iran's attack as "ineffective." Vice President Kamala Harris, the Democratic candidate for president, backed Biden's stance and said the US would not hesitate to defend its interests against Iran.
The White House similarly promised "severe consequences" for Iran and spokesman Jake Sullivan told a Washington briefing the US would "work with Israel to make that the case."
Projectiles were seen flying into Israeli air space after Iran launched its missiles. (EPA PHOTO)
UN Secretary-General Antonio Guterres condemned what he called "escalation after escalation", saying: "This must stop. We absolutely need a ceasefire."
French President Emmanuel Macron said in a statement that he strongly condemns Iran's new attacks on Israel, adding that in a sign of its commitment to Israel's security it mobilised its military resources in the Middle East on Wednesday.
British Prime Minister Keir Starmer spoke with the leaders of Germany and France, and they agreed on a need for restraint from all sides, Downing Street said.
Nearly 1900 people have been killed and more than 9,000 wounded in Lebanon in almost a year of cross-border fighting, most in the past two weeks, according to Lebanese government statistics on Tuesday.
