BEIJING - Three Chinese marine surveillance vessels on Friday morning entered the territorial waters around the Diaoyu Islands to carry out a patrol, according to the State Oceanic Administration (SOA).

Through a loudspeaker the fleet reaffirmed Chinese government's stance on the Diaoyu Islands to six ships from the Japan Coast Guard which had illegally entered the area. The fleet demanded they leave China's territorial waters around the islands, a SOA statement said.

A plane with Japan's maritime self-defense force and a helicopter from the Japanese media NHK were seen above the fleet, the statement added.

According to the SOA, the Chinese ships collected evidence of the Japanese ships and planes' infringement on China's sovereignty.