Senkaku Islands (sĕnˈkäkō) [key], small, uninhabited island group, 8 sq mi (20.7 sq km), Okinawa prefecture, extreme SW Japan, in the East China Sea. Located 90 mi (45 km) NNW of Ishigaki in the Ryukyu Islands, the group comprises five generally low-lying coral islands and scattered islets. Uotsuri-shima (2.5 mi/4 km long, 1 mi/1.6 km wide) is largest island. There are submarine oil deposits nearby. The islands, also known as the Pinnacle Islands and Diaoyu Islands, are claimed by China and Taiwan, and have been a source of regional tensions. Beginning in 2012 China repeatedly used ship and air traffic to challenge Japan's control of the sea and airspace surrounding the islands. In 2013 Japan and Taiwan signed an agreement that permits Taiwanese fishing in part of the exclusive economic zone around the islands.