The islands were called as Diaoyu islands by China and Senkaku by Japan. Japan controls waters around the disputed islets.
"These law enforcement and patrol activities demonstrated China's jurisdiction over the Diaoyu Island and its affiliated islets, achieved the goal of demonstrating China's sovereignty claim and ensured the country's maritime interests," said Xiao Huiwu, deputy chief of the headquarters of China marine surveillance.
On Friday, China sent six surveillance ships around Diaoyu Islands and started patrolling the area. It is the first time that Chinese surveillance ships have patrolled the area after the government here announced last week the base points and baselines of the territorial waters of the Diaoyu Island and its affiliated islets.
Three Japanese coast guard ships and three helicopters followed and monitored the Chinese ships and tried to intercept China's patrol activities, state-run Xinhua news agency reported. The two sides exchanged warnings through radio, it said.
