Japan put its navy on alert Wednesday after an unidentified submarine made a brief incursion into territorial waters near southern Okinawa, a top government official said.
The submarine left shortly after it was spotted. A P3C reconnaissance aircraft and destroyer were dispatched to monitor the vessel’s movements, Chief Cabinet Secretary Hiroyuki Hosoda said.
Defense chief Yoshinori Ono “issued a maritime alert order” after the submarine was spotted near the Sakishima islands in southern Okinawa prefecture (state), Hosoda said.
Prime Minister Junichiro Koizumi called the incursion “regrettable. It’s certainly not a good thing that a submarine of unknown national origin enters our territorial waters.”
Japan’s public broadcaster NHK said defense officials were investigating a possible link between the submarine and Chinese military vessels detected recently in Japan’s southern waters.
Defense officials confirmed that two Chinese military vessels — a submarine rescue craft and a towing vessel — were spotted over the weekend 195 miles southeast of Tanegashima island, which is 620 miles from where the submarine was discovered.
Japan has been studying methods for increasing its maritime defenses after a shoot out with a suspected North Korean spy ship in December 2001.
In that incident, Japanese Coast Guard patrol boats fired on and sank the suspected spy ship off southwestern Japan. The Japanese patrol vessels returned fire only after the ship was ordered to stop but opened fire with a rocket and guns.
The Sakishima islands lie in waters between the northeastern tip of Taiwan and Okinawa’s main island, 1,000 miles south of Tokyo.