TOKYO — Japanese military officials said they were closely watching seven Chinese warships spotted Tuesday in waters off a southern island.
It was unclear whether the ship movements were related to a territorial dispute that has prompted both countries to show off their maritime muscles.
The Chinese ships were sighted about 30 miles from the island of Yonaguni, in Japan’s Okinawa province, according to Japan’s Defense Ministry. They were about 125 miles from a chain of small islands that have sparked a heated dispute between Japan and China.
The ships were believed to be returning to China after training in the Pacific.
It is not unusual for the Chinese navy to transit waters around Okinawa en route to the Pacific, but this is the first such operation observed this year, according to public broadcaster NHK.
The ships included frigates, a guided-missile destroyer, a refueler and two submarine rescue vessels.
It was unclear if their mission was directly related to the territorial issue or whether they were trying to avoid an approaching typhoon.
China’s Defense Ministry said the ships were on a scheduled cruising exercise and were acting in a manner that was “appropriate and legal.”
Underscoring China’s sharper stance, it also protested the scrambling of a Japanese military plane in the direction of the disputed islands, calling that a “gross violation” of Chinese sovereign rights.
“The Chinese military is closely following the actions of the Japanese side and demands Japan halt all actions complicating or escalating the situation,” the ministry said in a short statement on its website.
Chief Cabinet Secretary Osamu Fujimura said Tokyo has urged Beijing to “avoid any actions that would go counter to the mutual benefit.”
Nearby Taiwan also claims the islands, which are uninhabited but surrounded by rich fishing grounds and possibly lucrative undersea energy deposits.
China and Japan recently have stepped up naval activities in the area around Okinawa because of the dispute, but there have been no clashes between their warships, which generally have stayed away from the islands.
Wary of missteps that could lead to a sudden escalation of tensions, the countries instead have sent less threatening coast guard ships.
Over the past week, however, both have made a point of showing off their naval prowess.
Chinese websites were abuzz Monday with photographs of navy pilots practicing touch-and-go landing exercises on China’s first aircraft carrier. It wasn’t clear when the pictures were taken, and they did not appear on the Defense Ministry’s website or in official media.
The carrier was launched last month without aircraft or an accompanying battle group, and flight operations could be years away.
Japan’s navy, meanwhile, marked its 60th anniversary with a major exercise on Sunday. Japan also plans to hold a joint exercise with the U.S. military later this year, reportedly using a scenario of taking a remote island back from a foreign intruder.