What is Israel's multi-layered defence against Iranian missiles?

Israel has multi-layered air defences against attacks by Iran, which has fired hundreds of ballistic missiles and suicide drones at Israel over the past two days as the Middle East rivals traded heavy blows.

Israel has been honing its air defences since coming under Iraqi Scud salvoes in the 1991 Gulf War, in addition to receiving support from the U.S., which has provided its ally with advanced anti-missile equipment.

An Israeli military official said on Saturday that the defensive umbrella had an "80 or 90% success rate", but emphasised that no system is 100% perfect, meaning that some Iranian missiles were breaking through the shield.

Here are details of Israel's missile defences:

ARROW

The long-range Arrow-2 and Arrow-3 interceptors, developed by Israel with an Iranian missile threat in mind, are designed to engage incoming targets both in and outside the atmosphere respectively. They operate at an altitude that allows for safe dispersal of any non-conventional warheads.

State-owned Israel Aerospace Industries is the project's main contractor while Boeing is involved in producing the interceptors.

DAVID'S SLING

The mid-range David's Sling system is designed to shoot down ballistic missiles fired from 100 km to 200 km (62-124 miles) away. 

Developed and manufactured jointly by Israel's state-owned Rafael Advanced Defense Systems and RTX Corp, a U.S. company previously known as Raytheon, David's Sling is also designed to intercept aircraft, drones and cruise missiles.

IRON DOME

The short-range Iron Dome air defence system was built to intercept the kind of rockets fired by Palestinian Islamist movement Hamas in Gaza.

Developed by Rafael Advanced Defense Systems with U.S. backing, it became operational in 2011. Each truck-towed unit fires radar-guided missiles to blow up short-range threats such as rockets, mortars and drones in mid-air. 

A naval version of the Iron Dome, to protect ships and sea-based assets, was deployed in 2017.

The system determines whether a rocket is on course to hit a populated area. If not, the rocket is ignored and allowed to land harmlessly. 

Iron Dome was originally billed as providing city coverage against rockets with ranges of between 4 km and 70 km (2.5-43 miles), but experts say this has since been expanded.

U.S. THAAD SYSTEM

The U.S. military said last October that it had sent the advanced anti-missile system THAAD, or the Terminal High Altitude Area Defense system, to Israel.

THAAD is a critical part of the U.S. military's air defences and is designed to intercept and destroy short, medium and intermediate-range ballistic missile threats in their terminal phase of flight.

The U.S. military helped to shoot down Iranian missiles fired at Israel on Friday, using ground-based systems, one U.S. official said. A U.S. Navy destroyer in the Eastern Mediterranean also helped to shoot down incoming ballistic missiles, Israeli media has reported.

AIR-TO-AIR DEFENCE

Israeli combat helicopters and fighter jets have fired air-to-air missiles to destroy drones that were heading to Israel, military officials have said.

Jordan’s air force also intercepted missiles and drones entering its airspace Friday, its state news agency said.