Raytheon Co., the world’s largest missile maker, plans to expand its Patriot air-defense system in the Persian Gulf as the world’s biggest oil-producing region strengthens its missile-defense, naval and air forces.

In Saudi Arabia, “we got an upgrade to the Patriot system that is in process,” Thomas Culligan, chief executive officer of Raytheon International Inc., told reporters late yesterday in Riyadh. “Hopefully, we will get a contract signed on that.”

Kuwait is upgrading and buying additional units, and Qatar “is looking at” the system, Culligan said. The United Arab Emirates bought a missile-defense system at a value not exceeding $3.3 billion at the end of 2008, according to a Raytheon statement on the company’s website.

Raytheon, based in Waltham, Massachusetts will provide as much as $4 billion in military equipment to Saudi Arabia as part of a larger U.S. weapons package to the kingdom, Culligan said. The U.S. Defense Department notified Congress on Oct. 20 that it plans to sell Saudi Arabia up to $60 billion in weapons to help confront threats from Iran and violent extremists based in Yemen.

The proposed sale, which may be the largest to another country in U.S. history if all purchases are made, includes Boeing Co. F-15 fighter jets and attack helicopters.

Saudi Upgrade

Saudi Arabia is upgrading its military after fighting for the three months Shiite Muslim insurgents along its border with Yemen. The Saudi military used Apache helicopters, F-15 jet fighters and artillery to dislodge the Houthi rebels after they seized territory in the kingdom. Fighting stopped in February.

The regional threat “is always an issue,” Culligan said. “I think that is driving some of this too. There is air defense but now you are moving to much more missile defense.”

Raytheon will supply advanced radar for F-15 planes for the kingdom’s Ministry of Defense and Aviation, Culligan said. Raytheon is also interested in expanding its training facilities and providing “homeland security” services and cyber protection in the kingdom, he said.

Saudi Arabia’s last significant U.S. weapons purchase was for 72 F-15s in 1992, a transaction valued at as much as $9 billion. The final instalment of those planes was delivered in November 1999. Saudi Arabia was among the top three buyers of U.S. defense equipment and services in three periods examined by the Congressional Research Service since fiscal 2001.