China on Thursday said it opposes the way Japan was handling the Chinese fishing boat incident.
"China will never accept the Japanese side's applying domestic law to the Chinese fishing boat operating in that area," Chinese Foreign Ministry spokeswoman Jiang Yu told the regular briefing.
Jiang said Japan's handling was "absurd, illegal and invalid."
Jiang's comments came after the Japanese coastal patrol handed the captain of the Chinese fishing boat it detained to local prosecutors earlier Thursday.
Two Japanese patrol boats collided with a Chinese fishing boat in waters off the Diaoyu Islands Tuesday. No injuries were reported from the collision, but then the fishing boat was intercepted by Japanese patrol boats.
"Japan should release the crew and vessel immediately and unconditionally so as to avoid an escalation of the incident," Jiang said.
Jiang emphasized that the Diaoyu Islands belong to China, and urged the Japanese side to "keep a sober mind" on the highly sensitive issue of territorial sovereignty.
"If not handled properly, (the issue) will seriously undermine the overall situation of China-Japan relations," Jiang said.
Jiang confirmed that China had sent a law enforcement vessel of the fishing administration to the waters near the Diaoyu Islands.
"The move is in accordance with Chinese law and aims at maintaining fishing and protecting the lives and property of Chinese fishermen in the waters," Jiang said.
Over the past two days, Chinese Foreign Ministry had lodged several representations to the Japanese side. The Chinese Embassy in Tokyo sent its staff to call on crew members, who were found to be safe and sound.
"Japan's illegal detention of the Chinese fishing boat and crew has sparked strong reactions from the Chinese people," Jiang said, calling for Japan to face up to the seriousness and graveness of the incident.
Stressing China exercises undisputed sovereignty over the Diaoyu Islands, Jiang said the Chinese government's will and determination to safeguard sovereignty and territorial integrity are unswerving.
She said it is a fact that China and Japan are divided as to which country has sovereignty over the Diaoyu Islands. "We maintain the issue should be properly resolved through negotiations and on the basis of respecting the facts."