Chinese fishery authorities concluded on Monday a week-long patrol mission that took four patrol ships to waters near the Diaoyu Islands.

Yuzheng 204 [file photo]

The Yuzheng-204 patrol ship returned to dock in Shanghai on Monday morning, after it conducted tasks with three other law enforcement vessels in the Chinese exclusive economic zone, including waters around the Diaoyu Islands.

China considers the Diaoyu Islands and affiliated islets inherent parts of its territory since ancient times. The China Fishery Administration Bureau has included waters near the Diaoyu Islands in regular patrols since 2010.

Three patrol ships, Yuzheng-202, Yuzheng-204 and Yuzheng-35001, arrived at areas near the Diaoyu Islands on Wednesday. The fleet regrouped after Yuzheng-202 left and Yuzheng-33001 joined in to continue the patrol.