Chinese marine surveillance ships continued their regular patrols in waters surrounding the territorial Diaoyu Islands on Thursday, the State Oceanic Administration (SOA) said.
A fleet consisting of three ships, the Haijian 51, Haijian 23 and Haijian 5001, carried out the mission, the SOA said in a brief statement.
During the patrol, the Chinese fleet spotted and monitored Japanese vessels that were illegally sailing in the area. They collected evidence on the Japanese ships and took law enforcement measures.