East China Sea tensions
The Chinese vessel lingered in contested waters for a few hoursReuters file photo

Japan has summoned the Chinese ambassador to Tokyo after Beijing's naval frigate sailed close to the disputed chain of islands in the East China Sea. Tokyo's foreign ministry said the Chinese vessel had sailed into its territorial waters.

The chain of islands, known as Senkaku in Japan and Diaoyu in China, has long been a bone of contention between the two Asian powerhouses. Although there has been relative calm during the past few months, China's latest act is likely to stoke fresh tensions.

Japan's foreign ministry said the Chinese ship entered the hotly contested waters shortly after midnight on 8-9 June and left the region after a few hours. The Chinese frigate was spotted by Japan's guided-missile destroyer Setogiri.

"The Senkaku Islands are inherently part of Japanese territory on the basis of history and international law. The government will take a resolute stance in fully protecting our territory on land and at sea," Chief Cabinet Secretary Yoshihide Suga told a regular press conference, according to Nikkei Asian Review.

Japan's Vice Foreign Minister Akitaka Saiki summoned the Chinese ambassador at about 2am local time to express displeasure over the episode. Local reports suggest there were three Russian vessels, including a destroyer, sailing in the region alongside the Chinese ship.

The relationship between Tokyo and Beijing began souring in 2012 after both countries stepped up their claims on the islands and Japan purchased them from a private owner. While China's patrol vessels have earlier entered the region, this is the first time a naval vessel has sailed into the stretch marking a sharp escalation of tensions.

In a statement sent to Reuters, China's Defence Ministry said: "Chinese naval ships sailing through waters our country has jurisdiction over is reasonable and legal. No other country has the right to make thoughtless remarks about this," adding that they are looking into the matter.