China's marine surveillance vessels continued routine patrols and law enforcement activities Sunday in territorial waters around the Diaoyu Islands in the East China Sea, the State Oceanic Administration (SOA) said.

Four China Marine Surveillance ships spotted Japanese Coast Guard ships and other vessels and declared the Chinese government's stance on the Diaoyu Islands to the Japanese ships, the SOA said.

The Japanese ships were told to immediately leave China's territory.

The fleet also monitored the ships for the purpose of collecting evidence of infringement on China's sovereignty, the SOA said.