south china seaTokyo protested to Beijing today after Chinese coast guard ships sailed into territorial waters surrounding disputed islands in the East China Sea, Japan.

According to Japan Coast Guard, Chinese vessels entered the waters surrounding islets, called the Senkaku in Japan and the Diaoyu in China, around 10.00 AM local time.

They left the territorial waters within an hour.

The director general of the Japanese foreign ministry’s Asian and Oceanian affairs bureau, Kenji Kanasugi, issued a protest today to the Chinese embassy in Tokyo, saying that the ship’s incursion violated Japan’s sovereignty.

The two countries are locked in a long-running dispute over the uninhabited islets. Tokyo has lodged at least 32 protests through diplomatic channels since August 5 over what it says have been about 30 intrusions by Chinese vessels in the territorial waters.

China is also involved in maritime disputes in the South China Sea with countries including the Philippines, but a UN-backed tribunal has ruled that Beijing’s claims were invalid.