The Obama administration has notified Congress of a possible sale to Turkey of advanced Patriot PAC-3 antimissile systems and related gear valued at up to $7.8 billion.

The primary contractors would be Raytheon Co and Lockheed Martin Corp, the Pentagon's Defense Security Cooperation Agency said in a notice made public on Friday.

The proposed government-to-government sale would include 13 Patriot fire units, 72 Patriot Advanced Capability (PAC-3) missiles and a range of related hardware.

Turkey would use the PAC-3 guided missiles to boost its missile-defense capability, strengthen its homeland defense and deter regional threats, the agency said.

Turkey is a partner of the United States in ensuring peace and stability in the region, it said. It is vital to the U.S. national interest to assist our North Atlantic Treaty Organization ally in developing and maintaining a strong and ready self-defense capability that will contribute to an acceptable military balance in the area.

The proposed sale of this equipment and support would not alter the basic military balance in the region, the agency said.

This would mark the first Turkish purchase of PAC-3 missiles, the notice said.

(Reporting by Jim Wolf, editing by Matthew Lewis)