Explosions and sirens could be heard in Israel on Sunday (NZ time), as Iran launched dozens of drones and missiles at its rival.
Iran said the attack was in response to a strike on its consulate in Damascus two weeks ago.
Where are the explosions taking place?
Multiple parts of Israel and the West Bank reported the sound of explosions.
CNN staff on the ground reported explosions above Tel Aviv appeared to be interceptions by Israeli air defences.
And in Jerusalem, CNN correspondent Nic Robertson said about 20 to 30 interceptions lit up the night sky.
The Israeli ambulance service said a 10-year-old boy has been critically injured, the first confirmed injury resulting from the attack.
In a briefing earlier on Sunday (NZ time), an Israeli military official said that more than 100 drones had been launched towards Israel from Iran. That number was later lifted to "more than 200".
There were reports some missiles had been launched by Iranian allies too, including Houthis in Yemen.
Two regional security sources said Jordanian jets shot down dozens of drones flying across northern and central Jordan. And the US also said it also shot down a number of drones in southern Syria and near the Jordanian border.
What has Israel said about the attack?
In an address to the nation, Israeli Prime Minister Benjamin Netanyahu said the military was "ready for any scenario".
He said in recent years, and especially in recent weeks, Israel had been preparing for a direct attack by Iran.
There were very few countries as prepared as Israel for an attack like this, with a stacked arsenal and experience with linked militant groups like Hamas and Hezbollah.
One of its best known air defence capabilities is the Iron Dome. But the Iron Dome does have limitations, and is best suited for rockets or missiles fired from short distances.
How has Iran responded?
Meanwhile, Iran suggested it will not launch further strikes against Israel.
Its Permanent Mission to the United Nations in New York said the attack was a response to Israeli "aggression against our diplomatic premises in Damascus" and it "deemed the matter concluded".
It warned against any retaliation or any involvement by the United States. Israel has promised a "significant response".
What has the international response been?
Jordan, Lebanon and Iraq have shut their airspace.
In the lead-up to the attack, Western leaders had been strongly urging against any escalation from Iran, warning that it could spread the conflict in Gaza into the wider Middle East. They have been quick to respond.
UK Prime Minister Rishi Sunak condemned the attack "in the strongest terms the Iranian regime's reckless attack against Israel".
He added: "Iran has once again demonstrated that it is intent on sowing chaos in its own backyard."
Sunak said the UK was urgently working to stabilise the situation with its allies and prevent further escalation.
US President Joe Biden has been given an update at the White House by his national security advisers.
He said the US' commitment to Israel's security against threats from Iran and its proxies was "ironclad."
UN head António Guterres has "strongly" condemned Iran's attack, saying "neither the region nor the world can afford another war".
"I am deeply alarmed about the very real danger of a devastating region-wide escalation. I urge all parties to exercise maximum restraint to avoid any action that could lead to major military confrontations on multiple fronts in the Middle East."