Earlier this week, the Washington Post reported that parts of the Thaad system were being moved to the Middle East, citing two officials.
The reports come as the US and Israel continue to strike Iran, and Iran responds with a barrage of drones and ballistic missiles targeting Israeli and US military bases in the region.
It’s not clear exactly how many missiles Iran has – it has launched more than 500 ballistic missiles so far, according to a New York Times tally.
Most of them have been intercepted but the volume of incoming fire could be straining Washington’s military inventory, observers say. And it’s likely to continue because Iran, they believe, is readying itself for a war of attrition that ensnares more of the Middle East, including US allies.
That would explain why Thaad – which is specifically designed to intercept high-altitude missiles – is crucial for bolstering the US’ defence system.
Reports earlier this month claimed that an Iranian strike destroyed the $300m radar of an existing Thaad system in Jordan.
Made by US company Lockheed Martin, the anti-missile system includes six mounted launches, with eight interceptors on each launcher, and a radar system for detection.
It can shoot down short and medium-range ballistic missiles, using hit-to-kill technology. That is, kinetic energy destroys the incoming warhead. It can do this at a high altitude, beyond even the Earth’s atmosphere, which was seen as especially useful in South Korea, because it could be used to intercept and destroy a nuclear warhead.
A single system, or battery as it’s known, costs roughly $1bn (£766m) and requires a crew of about 100 personnel to operate. The US operates just eight of them globally, two of which are in the Middle East – Jordan and Israel. The UAE and Saudi Arabia together own three more in the region.
The potential redeployment from South Korea is a “precautionary measure”, a US official told the Washington Post, but other analysts see a system stretched thin.
The move would strongly suggest “the need for the US to compensate for its heavy use of existing missile defence capabilities in the Middle East”, Professor John Nilsson-Wright of Cambridge University told the BBC.