The United States is providing Israel with one of its most advanced air defence systems to help defend against further Iranian ballistic missile attacks.
And in a rare move, it will also send about 100 troops to the country to operate it, the Pentagon said.
It will be the first deployment of American forces to Israel since the recent war in Gaza broke out in October 2023.
The US announced it would be providing a Terminal High-Altitude Area Defense (THAAD) battery just hours after Iran warned Washington to keep its forces out of Israel.
It also comes as the region braces for Israel's retaliation to Iran launching more than 180 missiles towards the country on October 1.
What can a THAAD system do?
The THAAD mobile system was specifically designed for ballistic missile defence.
Pentagon spokesperson Major General Pat Ryder said the battery would help "bolster" Israel's air defences in the wake of Iran's "unprecedented attacks against Israel on April 13 and again on October 1".
In its October attack, Iran fired a barrage of ballistic missiles at Israel, using some of its most advanced weapons.
It was much larger and more forceful than Iran's previous attack in April, putting greater stress on Israel's missile defences and allowing more warheads to get through.
The THAAD system can hit targets at ranges of 150 to 200 kilometres.
It will add another layer to Israel's already significant air defences, which include separate systems designed to intercept long-range, medium-range and short-range threats.
Israel's three key air defence systems:
- Iron Dome: Intercepts short-range surface-to-surface rockets (bottom layer)
- David's Sling: Intercepts short to medium, and medium to long-range surface-to-surface missiles (middle layer)
- Arrow 2 and 3: Intercepts medium to long-range, and long-range missiles (upper layer)
Malcolm Davis, senior analyst at the Australian Strategic Policy Institute (ASPI), said it made sense for the US to give Israel extra capabilities.
"I think it's probably sensible that the Americans deploy THAAD into Israel to complement the Israeli system," he told the ABC.
"There's a recognition that this war is going to continue, and it's probably going to escalate."
Israel already has US Patriot air defence systems in operation that can reach further than the Arrow 3.
The THAAD is considered a complementary system to the Patriot but it can defend a wider area.
The Patriot was designed purely to defend against missiles in their terminal phase, which is when they begin to re-enter the atmosphere.
A THAAD could also defend against missiles when they were mid-course, Dr Davis said.
It was not immediately clear where the THAAD battery was coming from or when it would arrive.
The US deployed one THAAD battery to the Middle East along with additional Patriot battalions to bolster protections for US forces in the region late last year after the recent conflict broke out between Israel and Hamas.
The war in Gaza began after a Hamas-led terror attack on October 7, 2023, on southern Israeli communities in which 1,200 people were killed and about 250 were taken hostage, according to Israeli tallies.
In response, Israel launched air strikes on Gaza that, along with a ground campaign, have killed more than 42,000 Palestinians.
US troops deployed to Israel
It is rare for US troops to deploy inside Israel, but the amount being sent is a typical number needed to operate THAAD batteries.
Generally, about 100 soldiers are needed for a THAAD system, which consists of six truck-mounted launchers, 48 interceptors, radio and radar equipment.
Dr Davis said the US troops would be there to ensure the THAAD was fully networked and integrated into existing air defences.
"They won't be anywhere near where the fighting is," he said.
Major General Ryder described the deployment as part of "the broader adjustments the US military has made in recent months" to support Israel and defend US personnel from attacks by Iran and Iranian-backed groups.
In recent months, US troops have aided Israel's defence from warships and fighter jets in the Middle East when it came under Iranian attack.
But they were based outside of Israel.
Ahead of the Pentagon's announcement, Iran's Foreign Minister Abbas Araghchi warned the US was putting the lives of its troops "at risk by deploying them to operate US missile systems in Israel".
"While we have made tremendous efforts in recent days to contain an all-out war in our region, I say it clearly that we have no red lines in defending our people and interests," he posted on X.
Drone swarm overwhelms Israeli system
Although Israel's air defences are among the most effective in the world, they are becoming increasingly compromised.
The Iron Dome has a 90 per cent success rate, according to the Israel Defence Force (IDF).
It has intercepted thousands of short-range rockets, missiles and drones over the past year.
But on Sunday night, local time, it was overwhelmed by a "swarm of drones" launched at northern Israel by the Lebanese militant group Hezbollah.
Some of the unmanned aircraft, which included drone models Hezbollah has not used before, penetrated Israeli air defence radars without being detected, the Iran-backed group said in a statement.
Israel's military said four of its soldiers were killed and seven severely injured in the incident near Binyamin, north of Tel Aviv.
The incident was being examined, the military said.
Matthew Levitt, a senior fellow at the Washington Institute, said the Iron Dome air defence system had failed.
"Things have gotten through before but never caused this much damage," he told ABC News.
"It appears the air sirens did not go off.
"No matter how you slice it, it was a tragedy and a failure of the Israeli system."
Drones are more difficult to intercept because they fly at a low level and can be launched in large numbers.
Although the Iron Dome was designed to counter drones, its weakness is that it can be overwhelmed.
"This is the nature of a threat of a war with Hezbollah," Dr Levitt said.
"If it can, it will fire as many rockets as possible."
Israeli forces and Hezbollah fighters in Lebanon have been clashing since October 8, 2023, when the group began firing rockets over the border in support of its ally Hamas in Gaza.
Late last month, Israel launched an intensive bombing campaign in Lebanon.
Lebanon's government says more than 2,100 people have been killed and 10,000 wounded in over a year of fighting, mainly over the past few weeks.
ABC/Wires
