Chinese Foreign Ministry spokeswoman Jiang Yu Thursday urged Japan to stop making irresponsible comments concerning China and take substantial action to safeguard bilateral ties.

Jiang's comment came in response to new Japanese Foreign Minister Seiji Maehara's criticism of China Wednesday over an incident in waters off the Diaoyu Islands involving a Chinese trawler and two Japanese coast guard vessels.

At a regular press conference, Jiang reiterated that the Diaoyu Islands and the adjacent islets have been an integral part of Chinese territory since ancient times.

"Japan's illegal detention of the Chinese fishing ship and its crew violated China's territorial sovereignty and the personal rights of the Chinese citizens," she said.

"The international community will draw its own conclusion about the cause of and responsibility for the incident," she added.

In a Foreign Ministry statement released Sept. 25, China made clear its solemn stance, she said.

"It not only demonstrates the determination of the Chinese government to safeguard its territorial sovereignty, but also embodies our sincere hope to foster sound China-Japan relations," she said.

When asked to comment on the Chunxiao oil and gas field issue, Jiang said China has complete sovereignty and jurisdictional rights over the Chunxiao oil and gas field, adding that Chinese activities in the area are reasonable and lawful.

"China's position on the East China Sea issue is solemn and serious," she said. "China does not want to see a further deterioration of the situation and hopes Japan will not create new barriers to bilateral ties."

China Thursday released three of the four Japanese who recently intruded into a Chinese military zone, after they admitted to having violated Chinese law and expressed regret for their mistake.

Jiang said the case remains under investigation and relevant authorities will handle the case according to law.