Biden watched in real time in Situation Room as more than 300 drones and missiles rained over Tel Aviv: Inside the tense preparations as White House braced for Iran to start smashing Israel

American officials breathed a sign of relief on Saturday night when they realized their preparations to help Israel, made over the past 10 days, had paid off and Iran had been thwarted.

President Joe Biden and his team were mindful the attack from Tehran 'could have caused an uncontrollable escalation abroad regional conflict, something we have worked day and night to avoid,' a senior administration told reporters in a briefing on Sunday.

Biden and his team watched - in real time in the White House Situation Room - as Iran sent over 300 aerial attacks into Israel. At one point, Tehran fired over 100 ballistic missiles at the same time, leading to a tense moment among the Americans, who said the level of force was at the 'high end' of what they expected.

'He was in the Situation Room getting real time updates, as this unfolded, including at the time of missile launches,' the official said of Biden, adding 'there was a bit of a relief, which you can imagine those tense moments,' when it was clear the attack was thwarted.

Two squadrons of U.S. Air Force F-15E Strike Eagles and anti-missile defenses shot from two U.S. aircraft carriers in the Mediterranean Sea helped Israeli defenses war off the attack, which left minimal damage.

'The United States enabled Israel to spectacularly defeat this unprecedent attack,' the U.S. official said, pointing out that 'President Biden is the first American President to directly defend Israel.'

APRIL 1 - THE INCIDENT IN SYRIA

A missile attack in Damascus, Syria, destroyed Iran's consulate building in the city and killed seven Revolutionary Guards, including the two generals.

Tel Aviv has not taken responsibility for the attack but Israel is believed to be behind it.

Israel has long targeted Iran's military installations in Syria and those of its proxies. 

APRIL 5 - PREPARATIONS BEGIN 

Biden  and his team starting preparations to help its Middle East ally.

Ten days ago, Biden ordered his team to 'defend Israel to the maximum extent possible,' a U.S. official said on Sunday.

That included beefing up America's military presence in the Middle East and continuous conversations between U.S. and Israeli officials.  

APRIL 10 - IRAN VOWS RETALIATION

Iran's Supreme Leader Ali Khamenei, in  an Eid al-Fitr speech, vowed retribution in the wake of the Damascus attack, for which Tel-Aviv has yet to take responsibility.

'When they attack the consulate, it is as if they have attacked our soil,' he said. 'The evil regime made a mistake and must be punished and it shall be.'

President Biden is hosting Japanese Prime Minister Fumio Kishida for a state visit.

On the sidelines of that visit by one of America's top Asian allies, Defense Secretary Lloyd Austin and National Security Adviser Jake Sullivan briefed the president on the possibility for additional U.S. military deployments, including a digital missile destroyer, which Biden immediately authorized.

APRIL 12 - REPORTS OF 'IMMINENT' ATTACK

Reports indicate an attack on Israel is 'imminent.'

Asked how imminent an attack on Israel may be, Biden said he didn't want to get into classified information but 'my expectation is sooner than later.' 

H is message to Tehran was 'don't.' 

'We are devoted to the defense of Israel. We will support Israel and help defend Israel and Iran will not succeed,' Biden said.

APRIL 13 - DAY OF ATTACK

U.S. officials said they were not given a direct head's up from Iran the attack was coming but still, Biden left his beach home in Rehoboth, Delaware, on Saturday afternoon amid fears an attack was imminent. 

He and his team watched the attack in real time in the White House Situation Room. 

At 9 p.m. ET Saturday night Biden spoke with Israeli Prime Minister Benjamin Netanyahu.

MISSILE COUNT 

Despite the days of preparation, the launches from Iran on Saturday night were at the 'high end' of what was anticipated, according to the officials.

'It's fair to say scope of this attack is on a high end,' a U.S. official said. 

'That is definitely on the high end, and makes it harder to defeat to defeat when you have that many missiles in the sky.'

It was estimated that Tehran fired more than 300 air threats – including more than 100 medium range ballistic missiles, more than 30 land attack cruise missiles and more than 150 one-way attack drones towards Israel.

'Iran's attack is completely unacceptable and reckless and risks dragging the region into broader conflict,' a senior U.S. military official said. 'These attacks also violated the airspace of neighboring countries.'

Biden and his team monitored the firings and interception attempts in real time in the White House Situation Room. 

The officials said there was 'relief' in the room once they saw that the missile defense efforts had succeeded and they noted the overwhelming majority of the intercepts of ballistic missiles on Saturday night was by Israeli systems.

The overnight attack used 'an array' of Israeli air defenses to ward off the missiles, said Lt. Col. Nadav Shoshani, a spokesman for the Israel Defense Forces.

That included the Arrow 2 and 3 systems, he said, designed to intercept missiles flying outside Earth's atmosphere and the top level of Israel's multilayered air defense network.

Most of the 120 ballistic missiles that Iran fired were also brought down, Israeli defense officials said. 

Ballistic missiles are usually harder to intercept due to their high speeds.

Israel's more widely known Iron Dome system, designed to intercept shorter range missiles and rockets, was also deployed.

The USS Arleigh Burke and the USS Carney, operating in the eastern Mediterranean Sea, engaged and destroyed between four and six Iranian ballistic missiles during the attack, military officials said. 

U.S. aircraft in the region shot down more than 70 Iranian drones; and a US Patriot battery shot down one ballistic missile in the vicinity of Erbil, Iraq.

France, Britain and Jordan also mobilized forces to help Israel fend off the attack.

'This was a coalition put together to help Israel defend itself,' National Security Council spokesman John Kirby said on ABC News's This Week. 'Iran is just increasingly further isolated in the region.' 

CALL WITH NETANYAHU

At 9 pm ET on Saturday night, President Biden in the White House Situation Room called Netanyahu, who was with his war cabinet in War Room 

The president 'told the Prime Minister that Israel really came out far ahead in this exchange,' a senior administration official said.

Biden also warned Netanyahu to think carefully about any escalation. 

'The president was very clear that we're going to help defend Israel, and he made very clear to the prime minister last night that we do have to think carefully and strategically about, you know, risks of escalation,' the official noted.

The White House repeatedly emphasized Saturday night's attack was a defeat for Iran and a win for Israel.

'Israel and coalition partners are able to defeat 99% of these munitions. There's virtually no infrastructure damage to Israel at all,' a senior administration official said.

And the White House warned Netanyahu it would not support Israel if it escalated the situation with Iran. 

'Our goal remains to de-escalate immediately and halt any further attacks. We do not seek conflict with Iran. But we will not hesitate to act to protect our forces and support the defense of Israel,' the official said.

APRIL 14 - THE AFTERMATH

Biden's packed agenda continued on Sunday where he had another meeting with his team in the Situation Room. That briefing included Sullivan, Austin, Secretary of State Antony Blinken and top advisers Brett McGuirk and Jon Finer.

The president also hosted a call with G7 leaders, and had a conversation with King Abdullah of Jordan.

Additionally, the president spoke with the top Congressional leaders: Senate Democratic Leader Chuck Schumer, Senate Republican Leader Mitch McConnell, Speaker Mike Johnson and House Democratic Leader Hakeem Jeffries.

President Biden also called Lieutenant Colonel Curtis - commander of the 494th fighter squadron, a united based at RAF Lakenheath in the United Kingdom, and Lieutenant Colonel Kevin Murphy, commander of the 3/35 fighter squadron unit from Seymour Johnson Air Force Base in North Carolina.

Both squads helped defend Israel and had dozen of aerial take downs. 

'The President expressed his thanks as their commander in chief for really their extraordinary airmanship and skill that was displayed throughout this multi hour engagement over the course of last night,' the White House said.