Japanese maritime authorities say three Chinese government ships have sailed into waters around disputed islands controlled by Tokyo, for the first time since late May.
The coast guard said three surveillance vessels were spotted inside the 22-kilometer zone off the unoccupied Senkaku islands, which China calls the Diaoyus, in the East China Sea shortly before 9:30 a.m. Friday.
The coast guard said it was warning the ships to leave the area.
Last September, Tokyo nationalized the islands, which have been the focus of a decades-long dispute. The resource-rich islands are also claimed by Taiwan.