Japan on Thursday lodged a protest with China after four China Coast Guard vessels entered Japanese waters around the disputed Senkaku Islands in the East China Sea and an apparent drone was seen flying above one of the vessels.
(Japan Coast Guard)
Japanese government sources said the Air-Self Defense Force scrambled an F-15 fighter jet in response to the deployment of a drone for the first time around the disputed islands also claimed by China.
Scrambling a jet against a small unmanned vehicle is another sign that Japan is on high alert over China's maritime assertiveness.
A high-ranking Japanese Foreign Ministry official lodged a protest with a senior diplomat at the Chinese Embassy in Tokyo, saying in a telephone call that the flying a drone over Japanese territory could escalate tensions near the Senkakus, a ministry official said.
The Chinese vessels entered Japanese territorial waters shortly after 10 a.m. and one of them appeared to be equipped with guns, the Japan Coast Guard said.
The coast guard ordered the Chinese vessels to leave the waters and they did so nearly two hours later. The apparent drone was seen above one of the ships sailing about 14 kilometers west-northwest of the Senkakus for about four minutes from around 10:52 a.m.
The drone later disappeared from sight, the coast guard said.
The waters around the uninhabited islets claimed by China and Taiwan, which respectively call them Diaoyu and Tiaoyutai, have rich fishery resources and possibly oil fields below the ocean floor.
Chinese government vessels last entered waters in the area on May 8.