A Chinese fishing boat collided with two Japanese patrol vessels on Tuesday in waters off the Diaoyu island, which China claims as its own, prompting Beijing to lodge protests with Tokyo.
"We have lodged solemn representations with the Japanese side," Chinese Foreign Ministry spokeswoman Jiang Yu told a media briefing.
The collisions occurred after the Japanese patrol vessels ordered the Chinese ship to stop for an inspection over alleged violation of international fishing laws.
No injuries were reported from the incident.
Jiang claimed that the Diaoyu islands and its adjacent islets had been Chinese territory since ancient times.
China urged Japanese patrol boats against any "so-called law enforcement activities" in waters off the Diaoyu islands and refrain from taking any actions that would threaten the security of Chinese fishing boats and their crew, Jiang said.
"We will closely follow the situation and reserve our right to take further action," she said said.
Japan has lodged protests with China several times over the entry of Chinese vessels into waters near the islands.