The Ground Self-Defense Force and the U.S. Marine Corps reached a secret agreement in 2015 to station a GSDF amphibious unit at the Marines' Camp Schwab in the Henoko district of Okinawa Prefecture, according to Japanese and U.S. government sources.

But the deal over a regiment of the Amphibious Rapid Deployment Brigade came without approval from non-uniform officials of Japan's Defense Ministry, prompting criticism from them that the GSDF acted against the principle of civilian control, the sources said Sunday.

The plan has been suspended due to the impasse between Okinawa and the Japanese government over the planned relocation of the Marines' Air Station Futenma from a densely populated area in Ginowan to the Henoko coastal area of Nago.