Two China Coast Guard (CCG) vessels patrolled territorial waters surrounding the Diaoyu Islands, on Thursday, according to a State Oceanic Administration statement.
The CCG 2350 and 2506 patrolled in the adjacent waters encompassing the Diaoyu Islands against rough oceanic conditions, the statement said.
During the patrol, the fleet safeguarded China's sovereignty in accordance with Chinese law and regulations against Japanese ships that had entered China's territorial waters.
The CCG, which covers maritime law enforcement functions of four agencies responsible for fisheries administration, maritime surveillance, customs enforcement and border control, formally unveiled its board in July.
On Sept. 9, the administration said that Chinese law-enforcement vessels have conducted 59 regular patrols around the Diaoyu Islands since September 2012, when Japan announced a plan to "purchase" the islands.
In the past year, Chinese ships have circled the islands at a minimum distance of 0.28 nautical miles.