TOKYO (Reuters) - Japan will protest to China after concluding that a nuclear-powered submarine that intruded into its waters this week belonged to the Chinese navy, top government spokesman Hiroyuki Hosoda said on Friday.
Japan mobilized its navy for the first time in five years on Wednesday after the submarine was spotted near the Okinawa islands, 1,000 miles southwest of Tokyo.
The intrusion was brief and no warning shots were fired, but the mobilization was a rare display of Japan's military response.
"We made an overall judgment that the submarine belonged to the Chinese navy," Hosoda told a news conference, adding that the decision was based on the direction the sub was taking and the fact that it appeared be nuclear-powered.
"Japan plans to lodge a protest with China."
Military analysts have said that, apart from the United States, China was the only country regularly operating nuclear-powered submarines in the area.
The Chinese Foreign Ministry had no immediate comment, but it was holding an emergency meeting and was conferring with other government departments over Japan's charges, a spokesman said.
Japanese media had quoted military sources as saying the submarine was Chinese, but the government had not previously confirmed those reports, some analysts saying that was because it did not want to worsen its fragile relations with China.
The incident has fueled fears in Japan about the military threat posed by China and is likely to further dent relations between the Asian neighbors, still plagued by memories of Japan's occupation of parts of China in the 1930s and 1940s.
China has been angered by Prime Minister Junichiro Koizumi's annual visits to Tokyo's Yasukuni Shrine, where war criminals are honored along with other war dead, and plans for a summit have been put on hold.
The two sides have been working toward holding a meeting between Koizumi and Chinese President Hu Jintao at this month's Asia-Pacific Economic Cooperation (APEC) meeting in Chile.
A meeting of leaders of the Association of Southeast Asian Nations (ASEAN) in Laos this month could provide another opportunity.
Hosoda said he did not know whether the submarine episode would scupper the chance of summit meetings, but added that there was no change to Japan's basic position of seeking friendly ties with China.
"I know that many of you are furious, but we have to look at the big picture," Hosoda told reporters.
"We have to see their response, but I think we have to deal with this calmly."
Other bilateral spats are festering.
Japan and China, along with Taiwan, have long disputed sovereignty over a cluster of islands in the East China Sea -- known as the Senkaku in Japan and the Diaoyu in China -- that are 124 miles northwest of the area where the submarine was seen.
Tokyo and Beijing are also at odds over a Chinese gas field project in a disputed part of the East China Sea, where Chinese research and naval ships have repeatedly entered Japan's exclusive economic waters without prior notice. (Additional reporting by John Ruwitch, Cher Gao and Zhou Xiqin in Beijing)
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