SHANGHAI - Three Chinese fishery patrol ships arrived at areas near the Diaoyu Islands around 2 am Wednesday during a routine check, according to fishery authorities.

A Chinese fishery patrol ship sails near the Diaoyu Islands, July 11, 2012.[Photo/Agencies]

The law enforcement vessels, Yuzheng-202, Yuzheng-204 and Yuzheng-35001, were conducting routine patrols of the East China Sea, said sources with the East China Sea Fishery Bureau under the Ministry of Agriculture.

The ministry had earlier issued a ban on fishing in the East China Sea from June 1 to protect fish during the spawning season.

In order to safeguard the interests of Chinese oceanic fishing industry and ensure safety of Chinese fishermen, the China Fishery Administration Bureau has included areas surrounding the Diaoyu Islands and affiliated islets in its regular patrol scope since 2010.

China considers the Diaoyu Islands and affiliated islets as inherent parts of its territory since ancient times.