Four Chinese marine surveillance ships patrolled in waters off the Diaoyu Islands on Sunday.
The patrol team, composed of the Haijian 51, the Haijian 66, the Haijian 75 and the Haijian 83, entered the waters after taking shelter at an anchorage to avoid approaching typhoons, according to a statement from the State Oceanic Administration.
They have been carrying out normal activities to safeguard China's sovereignty over the Diaoyu Islands, the statement said.
