TOKYO (REUTERS) - A Chinese coastguard ship equipped with what appeared to be four gun turrets was sighted near disputed islands in the East China Sea, Japan's coastguard said on Wednesday (Dec 23).
Chinese coastguard vessels sail regularly near the islets, but a Japanese coastguard spokeswoman told Reuters it was the first time an armed Chinese coastguard ship had been spotted in the area.
"We have delivered our strong protest and requested to stop the activities near the Senkaku Islands immediately," Takako Ito, a spokeswoman at Japan's Ministry of Foreign Affairs, said in an email.
She referred to the group of tiny, uninhabited islands by their Japanese name. They are know as 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 said.
The vessel, first sighted on Tuesday (Dec 22) afternoon, was sailing 29km off one of the contested islands as of 9am on Wednesday (Dec 23), Japan's coastguard said.
Sino-Japanese ties have long been mired by the dispute over the Japanese-controlled islands.
Patrol ships and fighter jets from both sides regularly shadow each other near the islands, stoking concern that an accidental collision could trigger a clash.
Japan said in 2013 a Chinese navy vessel aimed fire control radar, normally used to aim weapons at a target, at a Japanese navy ship in the East China Sea, prompting Japan to protest.