Raytheon is to modernize Kuwait's Patriot Air and Missile Defense Systems under a $523 million contract issued by the U.S. Army.

The Foreign Military Sales program award covers six Patriot fire units.

"Kuwait and other members of the 13-nation strong Patriot Partnership continue to invest in the system and trust Patriot to defend their citizens and militaries," said Ralph Acaba, Raytheon vice president of Integrated Air and Missile Defense. "Patriot is the only system in the world that is combat-proven and designed to outpace the future threat through continuous evolution."

The Patriot units will be upgraded by Raytheon to Configuration 3+, which features enhanced capability against a variety of threats, an improved identification-friend-or-foe capability and improved radar search.

The work by Raytheon is expected to be completed by 2022.

Patriot is a surface-to-air missile system for protection against cruise and tactical ballistic missiles and aircraft.