The United States and Japan on Monday began a drill in California that simulates retaking remote islands using MV-22 Osprey aircraft for landing exercises, at the request of the U.S. military.

It is the first time the Ground, Maritime and Air Self-Defense forces have jointly participated in such a drill on the U.S. mainland.

Around 1,000 SDF members are participating in the exercise through June 26. MSDF vessels involved include the Atago, a destroyer equipped with the Aegis missile interceptor system, and the helicopter-carrying destroyer Hyuga.

Defense Minister Itsunori Onodera said in Tokyo on Tuesday that the U.S. Marine Corps tilt-rotor Ospreys will land on the MSDF ships during the drill.

"It will help boost technical cooperation," Onodera said. "The United States made such a proposal to us as we tried to find ways to cooperate between the (Japanese and U.S.) units."

The drill is intended to reinforce the SDF's ability to defend remote islands amid Tokyo's ongoing dispute with Beijing over the sovereignty of the Japan-held Senkaku Islands in the East China Sea.

Tokyo and Washington say they had no particular enemy country in mind while planning the drill, but Beijing has still requested that the exercise be halted. The training is part of the broader Dawn Blitz joint drills involving the United States, Canada and New Zealand.