The United States in June 1978 instructed its navy to suspend use of a firing range that Japan had provided as a training ground in the Senkaku Islands over fears that it could become embroiled in a Sino-Japanese territorial dispute, according to declassified U.S. government documents.

The documents, obtained by Kyodo News from the U.S. National Archives, also showed that the U.S. government rejected a request by its military the following year to resume use of the firing and bombing range near Taisho Island, known as the Sekibi-Sho Range.

File photo taken on Sept. 22, 2012 shows Taisho Island, one of the islets in the Japan-controlled Senkaku Islands in the East China Sea. China claims the uninhabited islands. (Kyodo)

Taisho is part of the Japanese-administered Senkakus in the East China Sea. China claims the Senkakus and calls them Diaoyu.

According to the Japanese government, the U.S. military has not since notified Tokyo of any use of the firing range, suggesting it is possible that the U.S. government's instructions as of June 1978 remain in effect to this day.

Successive U.S. administrations, including the current administration under President Joe Biden, have made the Senkakus subject to Article 5 of the Japan-U.S. security treaty.

Article 5 states the United States will defend territories under Japan's administration from armed attack.

But the United States maintains a neutral position regarding the territorial dispute, saying it is an issue between the involved parties.

The declassified documents reveal that the United States distanced itself from Japan, one of its allies, in order to avoid direct confrontation with China over the issue of territorial sovereignty.

Administrative rights over the Senkakus were returned by the United States to Japan in 1972 as part of the reversion of Okinawa.

At that time, Japan ensured the continued use by the U.S. military of the Sekibi-Sho Range and another firing and bombing range in the Senkaku Islands by providing their use under the Status of Forces Agreement between the two countries.

Since the U.S. military has not notified the Japanese government that it intended to use the other range near Kuba Island since June 1978 either, there is a possibility that Washington has applied the same policy to both ranges.

China has stepped up its claim after Japan brought the islands under state control in 2012. Japan takes the position that there exists no issue of territorial sovereignty to be resolved over the islands.