Beijing : A Chinese marine surveillance fleet continued patrolling around the Diaoyu Islands Monday and monitored Japanese ships that entered the islands' waters.
The vessels -- Haijian 137, Haijian 23 and Haijian 46 -- followed and engaged in surveillance of the Japanese ships, solemnly declared China's sovereignty over the islands and sought the Japanese ships' immediate departure from the area, China Daily quoted the state oceanic administration as saying.
Last year, surveillance ships carried out 58 patrol missions in the South China Sea over its territorial waters off the disputed Diaoyu Islands to secure the nation's maritime rights and interests.
The islands are called "Diaoyu" in China but "Senkaku" in Japan. The row over the islands, which are presently controlled by Japan, has left ties between Tokyo and Beijing highly tense.
Japan claims occupying the islands since 1895, while China maintains the islands were recognised as Chinese territory as early as 1783.
The islands, which are also claimed by Taiwan, potentially contain large reserves of hydrocarbons.