China Marine Surveillance airplane B-3837 entered the airspace over the Diaoyu Islands in the East China Sea at around 10 am on Thursday, joining the routine patrol with four marine surveillance ships, the State Oceanic Administration said in a statement.

A statement released by the administration on its official website on Thursday said Haijian 50, 46, 66 and 137 were patrolling the waters near the Diaoyu Islands while B-3837 arrived in the airspace above them.

During the patrol, the fleet declared the Chinese government's stance regarding the Diaoyu Islands to Japanese ships that had illegally entered the waters and asked them to leave the waters, according to the statement.

Since Japan's illegal "purchase" of the Diaoyu Islands, China Marine Surveillance vessels have patrolled the waters consistently and released timely statements on the patrols to the public on the State Oceanic Administration's website.