The hiker's GPS watch, which uses satellite signals to log routes and monitors heart rate, was retrieved after the fatal attack, the Asahi Shimbun reported.

Kareem El, a civilian from Washington, D.C., visiting Okinawa, was held by U.S. military police for declining to provide identification.

This follows joint drills by Chinese and Russian strategic bombers and fighters on Tuesday that prompted Japan and South Korea to scramble planes to monitor them.

NANJING, China, Dec 13 (Reuters) - China held a low-key memorial ceremony on Saturday for the 1937 Nanjing Massacre, with President Xi Jinping not attending, despite a diplomatic crisis between Beijing and Tokyo over Taiwan.

As tensions between China and Japan rise, the sparsely populated island of Yonaguni finds itself right on the front lines.

Two Russian strategic bombers Tu-95 that flew down from the airspace east of the Korean Peninsula joined a pair of Chinese H-6 bombers over the East China Sea for a joint flight down to the Pacific off the southern coast of Japan's Shikoku island.

By Daphne Psaledakis and John Geddie WASHINGTON/TOKYO, Dec 10 (Reuters) - The United States has for the first time criticised China for aiming radars at Japanese military aircraft during a training exercise last week,