YOKOHAMA, Japan (Kyodo) -- Japan lodged a protest with China on Saturday after the Japan Coast Guard detected a Chinese research vessel navigating in the nation's exclusive economic zone.
The incursion followed similar cases in March 2016 and December last year, according to the coast guard. China has said it was operating on the high seas, not in Japan's 200-nautical mile EEZ.
A coast guard aircraft spotted the Chinese vessel around 12:30 p.m. off Okinotori Island, a remote atoll in the Western Pacific that Tokyo claims as a base point for its EEZ.
The plane contacted the ship and asked it stop its operations but it did not respond, said the coast guard.
China has said that Okinotori is just "rock" and rejects Japan's claim that it is a base point for the country's EEZ.