Beijing has called sailings by its warships through the Tokara Strait off Kagoshima Prefecture "legal" under international law, days after Tokyo said a Chinese military survey vessel had entered Japan's territorial waters in the area.

The sailing was part of a series of recent moves by the Chinese military near Japan that Tokyo has said are “cause for concern.”

China’s Foreign Ministry on Monday called the nearly 200-kilometer strait one used “for international navigation,” according to the United Nations Convention on the Law of the Sea (UNCLOS).