A U.S. expert has stressed the urgent need for strengthening the functions of the U.S. military command in Japan in order to promote coordination with the Japanese Self-Defense Forces.

The U.S. military's Operation Tomodachi relief activities conducted jointly with the SDF after the 2011 massive earthquake and tsunami that hit northeastern Japan "was the most significant bilateral effort to carry out operations together," James Schoff, senior director at Sasakawa Peace Foundation USA in Washington, said in a recent interview.

Although the operation was successful overall, "there were challenges and difficulties" in a variety of areas, including on the decision-making front and in terms of how the U.S. military and the SDF shared information, Schoff, who studies the modernizing of Japan-U.S. command and control relationships, said in the interview prior to a Japan-U.S. summit in Washington scheduled for this week.