The Japanese government says it has lodged a protest with Beijing, after finding a buoy placed by China in Japan's exclusive economic zone.

The government said the Japan Coast Guard found a Chinese buoy near the Senkaku Islands in Okinawa Prefecture in July.

The government said it issued a warning about the buoy on July 15 to ensure the safety of vessels navigating in the area.

On Tuesday, Chief Cabinet Secretary Matsuno Hirokazu told reporters that setting up structures in Japan's exclusive economic zone without its consent violates rules related to the UN Convention on the Law of the Sea.
He said the government has lodged a protest with China through diplomatic channels, and has demanded the immediate removal of the buoy.

Matsuno said that relevant ministries will work together to take all necessary measures to ensure the safety of vessels in the area, as well as to conduct surveillance activities. He said the government will respond resolutely and calmly to protect Japan's territory, territorial waters and airspace.

Japan controls the Senkaku Islands. China and Taiwan claim them. The Japanese government maintains the islands are an inherent part of Japan's territory, in terms of history and international law. It says there is no issue of sovereignty to be resolved over them.