BEIJING - Chinese marine surveillance vessels on Friday monitored Japanese ships illegally entering the territorial waters around the Diaoyu Islands during the fleet's routine patrols, according to the State Oceanic Administration (SOA).

The fleet entered the waters around 10:30 am (Beijing Time) to conduct routine patrols and law enforcement activities. It monitored the Japanese ships for the purpose of collecting evidence of infringement on China's sovereignty, said the SOA in a statement released on Friday.

China's surveillance ships also declared the Chinese government's stance on the Diaoyu Islands to the Japanese ships, the statement added.