ISTANBUL

China and Japan on Monday engaged in a verbal duel over disputed islands in the East China Sea.

Tokyo lodged a protest with Beijing after Chinese and Russian warships were seen sailing “just outside Japanese territorial waters” around the Senkaku Islands in the East China Sea, the Japanese government said.

“Japan will respond firmly but in a calm manner against similar moves,” said Seiji Kihara, a Japanese government spokesperson.

However, Beijing retorted, saying Tokyo “has no right to make irresponsible remarks.”

Beijing and Tokyo are locked in a dispute over the Japanese-controlled uninhabited Senkaku Islands, which Beijing claims and calls Diaoyu.

“The Diaoyu Islands and their affiliated islands are China's inherent territory,” said Zhao Lijian, spokesperson for China’s Foreign Ministry.

“Chinese vessel’s activities in nearby waters are legitimate,” Chinese daily Global Times quoted Zhao.

The Chinese frigate sailed in the contiguous zone of the uninhabited islets for about six minutes early Monday morning, and shortly after a Russian frigate entered the waters, the Japanese Defense Ministry said.

“It was the first time since June 2016 that Chinese and Russian naval vessels had been spotted entering the contiguous zone at around the same time,” said a report by Tokyo-based Kyodo News.

Takehiro Funakoshi, a senior Japanese Foreign Ministry official, also spoke to a Chinese diplomat in Tokyo to protest the China-Russia move.

Japan and China had agreed in 2008 on joint gas development in the area but negotiations were suspended in 2010 when tensions between them increased following a Chinese trawler’s collision with a Japan Coast Guard vessel.​​​​​​​