State of play: While most missiles were intercepted, "several hits were identified, and the damage is being assessed," an Israeli official said.

• President Biden and national security adviser Jake Sullivan both described Iran's attack as "defeated and ineffective" and said the U.S. stands with Israel.
• Sullivan said Iran had launched almost 200 missiles but that most had been intercepted by U.S. Navy destroyers and Israel's air defense systems.

What's next: Iran said the attack was launched in retaliation for a string of recent Israeli assassinations, but that it was now over, and that Israel would face "a crushing defeat" if it responds with force.

• IDF spokesperson Daniel Hagari said in televised remarks: "We will protect the citizens of Israel. This attack will have consequences. We have plans. We will act at the time and place of our choosing."
• "This is a significant escalation on the part of Iran. There will be severe consequences for this Iranian attack and we will work with Israel to make sure that is the case," Sullivan said.

How it happened: Numerous explosions were reported in central Israel, and Israeli missile defense systems lit up the sky as they activated to intercept the incoming missiles. Sirens sounded across much of Israel as the attack began.

• Hagari said IDF missile defense systems "made quite a few interceptions." He noted that several missiles hit areas in the center and the south of Israel with no casualties known to the IDF.
• During the attack, the Israeli Security Cabinet convened at the government bunker near Jerusalem, while President Biden and Vice President Kamala Harris watched from the Situation Room.
• The U.S. warned Israel of an imminent ballistic missile attack at around 5am ET, a senior Israeli official said. Before any missiles were launched, the White House warned Iran it would face "severe consequences."
• Israeli airspace was closed to all civilian flights but later reopened.

The big picture: Israel is at war with two of Iran's allied militias, Hamas and Hezbollah. Fears of a broader war involving Iran itself have been growing for weeks.

• Iran has said it wants to avoid a regional war, but Tuesday's attack is two months in the making.
• Iran said it was acting in retaliation for Israel's assassinations in April of Hamas leader Ismail Haniyeh in Tehran, and for the attack last week in Beirut that killed Hezbollah leader Hassan Nasrallah and senior Iranian Gen. Abbas Nilforoushan.

Zoom in: The use of ballistic missiles made this a more difficult attack for Israel to defend against than the Iranian drone and missile attack last April — Iran's first-ever direct attack on Israeli territory — which was largely repelled by Israel and its partners, led by the U.S.

• Ballistic missiles can reach Israel within 12 minutes, while drones and cruise missiles leave more time to defend against.

Zoom out: The warnings of an imminent attack came just hours after Israel escalated its conflict with Hezbollah, the Iran-backed militia, by launching a ground invasion of southern Lebanon.

• Iran has been promising retaliation against Israel for two months, since the assassination of Haniyeh in Tehran.
• Iran had yet to respond to that attack, and also rebuffed urging from Hezbollah to launch an attack against Israel within the past two weeks, Axios reported.
• U.S. and Israeli officials had been concerned that the Israeli ground invasion and the assassination of Nasrallah — a longtime ally of Iran's supreme leader — would push Iran to change course and get more directly involved to save the militia it has armed and supported for decades.

Flashback: Iran launched a massive drone and missile attack against Israel in April in retaliation for another Israeli airstrike that killed a top Iranian general in Syria.

• Most of the drones and missiles were intercepted by Israeli, U.S., British, French, Jordanian and Saudi forces outside of Israeli airspace, and there were several injuries in Israel but no fatalities.

What to watch: Israel's retaliation for that attack was relatively small in scale, but Israeli officials made clear that this time the Israeli response will be much stronger.

• An IDF official told reporters that on Tuesday night the Israeli Air Force is going to "continue conducting powerful strikes all over the Middle East."

This is a breaking news story and will be updated.