"The area is a Chinese traditional fishing ground where Chinese fishermen from coastal provinces including Fujian and Zhejiang have been fishing for generations," said Guo Shijun, the commander of the mission.

The Diaoyu Islands [file photo]

"We have met with Chinese fishery ships many times during our mission and helped guide their production. We also asked them to inform us if they are harassed by foreign ships," Guo said.

The patrol ships also encountered Japanese Coast Guard ships on Wednesday and engaged in a verbal confrontation with them, the commander added.

"Five large patrol ships from the Japanese Coast Guard have followed us and interfered with our mission. Japanese aircraft also hovered above our ships several times," according to Guo.

"We have reiterated that the waters near Diaoyu Islands are within Chinese territory, and asked Japanese vessels to stop harassment and withdraw from waters under Chinese administration immediately."

Chinese fishery patrol ships will conduct further missions in the Chinese exclusive economic zone after a short break, according to China's fishery authorities.