China Tuesday demanded Japan "immediately terminate so-called 'legal procedures'" against the detained captain of a Chinese fishing boat and his safe return home as soon as possible.

Chinese Foreign Ministry spokeswoman Jiang Yu made the remarks at a regular press briefing, calling it "an imperative matter."

Jiang's comment came a day after 14 crew members of a Chinese trawler returned to China after they and the boat were illegally detained by Japanese authorities near the Diaoyu Islands in the East China Sea last Tuesday.

Japan is still holding Zhan Qixiong, the trawler's captain.

Jiang said a delegation of China's National People's Congress, China's parliament, had agreed to postpone a scheduled visit to Japan. The decision was made after "taking into consideration all aspects."

"Japan stirred up the current grave situation and the Japanese side should hold all the responsibility," she said.

Jiang said the Chinese people had expressed their rage after the incident, showing "their firm will and determination to safeguard China's sovereignty and territory."

Referring to a Japanese elementary and junior high school hit by stones in Tianjin, Jiang said the Chinese government had always protected the safety of foreign organizations and people in China and would do so in the future.

"We do not approve of isolated radical activities and we believe the Chinese people will express their will in a rational way," Jiang said.

She reiterated that China's stance on the Diaoyu Islands was "clearcut."

"The Diaoyu Islands have been China's territory since ancient times and such a fact cannot be changed by anyone," she said.

"China was the first country to discover the Diaoyu Islands and execute effective jurisdiction over the islands. China processes indisputable sovereignty over the Diaoyu Islands and China's willingness and determination to safeguard its sovereignty and territorial integrity is unshakable," she said.

The fishermen were illegally detained after their trawler collided with two Japanese Coast Guard patrol vessels. After China lodged representations with Japan, all the crew, except the captain, returned to the southeastern city of Fuzhou on a flight chartered by the Chinese government Monday.

The trawler is en route to China under escort of two Chinese fishery administration ships.