The plan involves integrating battle management, command, control, communications and intelligence of the two missile defense systems.

The agency hopes to create the integrated missile defense force as early as 2006 when Japan introduces two U.S. missile defense systems to cope with missile attacks. This would be the first inter-service combat unit in the Self-Defense Forces.

The decision is part of the Defense Agency's plan to integrate the overall operations of the Self-Defense Forces. The agency plans to draw up bills revising the Self-Defense Forces Law and the Defense Agency Law for submission to the regular Diet session in 2005.

The integrated missile defense force would have six Patriot Advanced Capability-3 (PAC-3) batteries and one Aegis destroyer.

Defense Agency Director General Shigeru Ishiba and U.S. missile defense chief Lt. Gen. Ronald Kadish agreed in June to step up cooperation on ballistic missile defense based on a U.S. program for a layered system -- a combination of an Aegis ship-based midcourse interception system and a Patriot ground-to-air system.

The Defense Agency has decided to introduce the two U.S. missile defense systems and plans to formalize the decision by the end of this year. Deployment of the integrated missile defense force would cost more than 1 trillion yen.

The missile defense system based on Aegis destroyers is designed to intercept short- and medium-range ballistic missiles at midcourse. The PAC-3 ground-to-air antimissile system, which will upgrade the Air Self-Defense Force's PAC-2 system, is designed to knock out missiles missed by Aegis destroyers.