A Chinese aircraft carrier for the first time passed through a narrow waterway between Yonaguni and Iriomote islands in Okinawa Prefecture on Wednesday, the Defense Ministry in Tokyo said, the latest in a spate of moves in the region by Beijing.

According to a map released by the ministry, China’s Liaoning carrier and two other ships accompanying it also entered Japan's so-called contiguous zone — international waters that extend an additional 12 nautical miles (22 kilometers) beyond its territorial seas 12 nautical miles from its shores. The waterway itself is only about 65 km — 35 nautical miles — wide.

Under international law, vessels from other countries are allowed to travel in Japan’s contiguous zone, though it can take measures if a ship enters its territorial waters.