A seven-ship fleet of the China Coast Guard is now patrolling China's territorial waters surrounding the Diaoyu Islands.
The Chinese ships are circling the islands in two groups, in opposite directions. They are monitoring a similar number of Japan Coast Guard ships.
According to China's State Oceanic Administration, the law enforcement patrol will continue for 4 hours. Routine patrols began a year ago after Japan proposed nationalising the islands.
The move shows China's determination to maintain its sovereignty and safeguard its maritime interests.