TOKYO, Dec 23 (Reuters) – A Chinese coastguard ship outfitted with what seemed to be 4 gun turrets was sighted close to disputed islands within the East China Sea, Japan’s coastguard mentioned on Wednesday.

Chinese coastguard vessels sail commonly close to the islets, however a Japanese coastguard spokeswoman informed Reuters it was the primary time an armed Chinese coastguard ship had been noticed within the space. For its half, China mentioned the vessels have been carrying commonplace gear and doing nothing fallacious in Chinese waters.

“We have delivered our strong protest and requested (the Chinese coastguard) to stop the activities near the Senkaku Islands immediately,” Takako Ito, a spokeswoman at Japan’s Ministry of Foreign Affairs, mentioned in an e mail.

She referred to the group of tiny, uninhabited islands by their Japanese identify. They are know because the Diaoyu in China.

“Japan will continue to act firmly and calmly, under the principle of resolutely defending our territorial land, sea and air,” she mentioned.

Chinese Foreign Ministry spokesman Hong Lei reiterated China’s stance that the islands have been Chinese territory since historic instances.

“Patrols by Chinese coastguard ships in the relevant seas are beyond reproach,” Hong mentioned at a every day information briefing. “The equipment on Chinese coast guard vessels is standard equipment and no different from international practice.”

The vessel, first sighted on Tuesday afternoon, was crusing 29 km (18 miles) off one of many contested islands as of 9:00 a.m. (0000 GMT) on Wednesday, Japan’s coastguard mentioned.

Sino-Japanese ties have lengthy been mired by the dispute over the Japanese-controlled islands.

Patrol ships and fighter jets from either side commonly shadow one another close to the islands, stoking concern that an unintended collision might set off a conflict.

Japan mentioned in 2013 a Chinese navy vessel aimed fireplace management radar, usually used to purpose weapons at a goal, at a Japanese navy ship within the East China Sea, prompting Japan to protest.

China additionally claims many of the energy-rich South China Sea, by means of which $5 trillion in ship-borne commerce passes yearly. The Philippines, Vietnam, Malaysia, Taiwan and Brunei have overlapping claims.

(Reporting by Nathaniel Taplin in SHANGHAI, Kiyoshi Takenaka and Lisa Twaronite in TOKYO and Ben Blanchard in BEIJING; Editing by Dean Yates and Nick Macfie)

(c) Copyright Thomson Reuters 2015.