The Defense Ministry said about 1,000 Self-Defense Forces personnel will participate in a U.S. drill in California in June to practice recapturing an isolated island.
It will be the first time for SDF personnel to participate in such an exercise on the U.S. mainland.
The move could trigger a backlash from China because the Defense Ministry has been strengthening its capability to protect isolated islands amid the deterioration in bilateral ties being caused by the Senkakus dispute, experts on defense issues said.
A Defense Ministry official said Tuesday the drill will not be premised on regaining control of an island from a specific country, and that the SDF will take part simply because the United States is a suitable place to do it.
Personnel from all three SDF branches will participate in the exercise, which will be conducted at Marine Corps Base Camp Pendleton and on San Clemente Island. The Maritime Self-Defense Force destroyer Hyuga will take part.