Japan put its naval forces on alert Wednesday after the government said an unidentified submarine had intruded into southern Japanese waters, near Okinawa. VOA's Steve Herman reports from Tokyo.
Japan's maritime forces were placed on a alert and tracked a submarine that apparently intruded into its territorial waters Wednesday morning.
Chief Cabinet Secretary Hiroyuki Hosoda says the foreign submarine headed back out into the open sea shortly after it was detected between Ishigaki and Miyako islands in Okinawa Prefecture.
Mr. Hosoda says a Maritime Self Defense Force (P3C) aircraft is tracking the submarine to try to determine its origin and where it is heading.
Suspicions immediately fell on China and North Korea. Quasi-official broadcaster NHK quotes Chinese Embassy officials here as saying they had no information about whether the submarine might be from China.
In December 2001, a suspected North Korean spy ship sank in the East China Sea after an exchange of fire with the Japanese Coast Guard.
The submarine incident comes after South Korea's Navy said a North Korean patrol boat briefly strayed into South Korean waters in the Yellow Sea for about 40 minutes Tuesday evening.
Military officials in Seoul say the boat was apparently in pursuit of a Chinese fishing vessel.
South Korean officials say three warning messages were sent to the North Korean boat, which replied it was attempting to keep control of ships in their waters.
Last week, South Korea's navy fired warning shots in the same area after three North Korean patrol boats crossed the frontier in two separate incidents. North Korea later accused the South of a grave provocation that could lead to a clash.
Meanwhile, South Korean Foreign Minister Ban Ki-moon expressed optimism Wednesday about hopes for another round of multilateral talks about North Korea's nuclear weapons development.
Mr. Ban, speaking at a forum, said a fourth round of six-nation talks could follow this week's discussions in Pyongyang between Japan and North Korea.
A delegation from Tokyo is in the North Korean capital hoping to learn more about Japanese kidnapped decades ago by North Korean agents.
Three rounds of talks - involving both Koreas, the United States, China, Japan and Russia - have not resulted in any breakthroughs.