The Defense Agency is planning to procure 124 Patriot surface-to-air missiles by the end of fiscal 2010 and to have a domestic defense contractor build them to replace imports, which will meet initial demand, informed sources said Saturday.

The plan to procure Patriot Advanced Capability 3 missiles for deployment by the Air Self-Defense Force is part of the agency's missile defense program.

The PAC-3 missiles are intended to hit incoming missiles at an altitude of up to 20 km that have escaped interceptor missiles launched by Maritime Self-Defense Force vessels equipped with the Aegis air-defense system.

Costing an estimated 500 million yen each, the missiles will first be imported from the United States, but the agency is planning to switch to delivery from Mitsubishi Heavy Industries Ltd., which will be licensed to produce them domestically, the sources said.

The agency plans to extend the missile defense system first to Tokyo and six other major urban centers.

"Defensive coverage is limited and other areas (not covered) will be dependent on interception from Aegis ships," a senior ASDF officer said.

Four bases in Saitama, Shizuoka, Gifu and Fukuoka prefectures will each get four PAC-3 launch systems between fiscal 2006 and 2010. There will also be two backup units.

Of the 18 systems, 15 will have eight missiles each, the sources said.

The first batch of 32 missiles for the Saitama base will be U.S.-built, while the remainder will be made in Japan.