The Terminal High Altitude Area Defence (THAAD), which has already been supplied to Saudi Arabia's neighbours Qatar and the United Arab Emirates, is one of the most capable anti-missile batteries in the US arsenal and comes equipped with an advanced radar system.
Saudi Arabia had asked to buy 44 THAAD launchers and 360 missiles, as well as fire control stations and radars.
"This sale furthers US national security and foreign policy interests, and supports the long-term security of Saudi Arabia and the Gulf region in the face of Iranian and other regional threats," the Pentagon's Defense Security Cooperation agency said in a statement on Friday.
The sale can go ahead if the US Congress does not object within 30 days."
