The Defense Agency is planning to launch a study group by the end of August to research legislation ensuring that U.S. forces in Japan operate smoothly during domestic military crises, agency sources said Sunday.

The study on the U.S. military's joint role with Japan's Self-Defense Forces in emergencies will examine topics such as enabling U.S. forces to expropriate land and facilities, exempting U.S. personnel from Japanese road and air traffic laws and the logistics of supplying the forces, they said.

The group will later consider whether to expand the implementation of the Japan-U.S. Acquisition and Cross-Servicing Agreement -- the application of which is currently limited to contingencies near Japan -- to include foreign attacks on the country.