Vice-Foreign Minister Song Tao summoned Japanese ambassador to China Niwa Uichiro to "lodge solemn representations", the Xinhua News Agency reported.

Earlier in the day, two Japanese patrol boats collided with the Chinese trawler.

The protest came after a ministry spokeswoman expressed "grave concern" over the collision.

Jiang Yu, speaking at a regular news briefing, urged Japan to stop its so-called law enforcement in waters off the islands and refrain from taking any action that would threaten the security of Chinese fishing boats and their crew.

"We have lodged solemn representations with the Japanese side," Jiang said, adding, "we will closely follow the situation and reserve our right to take further action".

The Diaoyu Islands and its adjacent islets have been Chinese territory since ancient times, Jiang reiterated.

The incident occurred when three Japanese patrol boats stopped a Chinese trawler claiming it was operating illegally near the islands before ordering it to leave the area, according to Japan's Mainichi Daily News.

The Chinese trawler's bow hit the 1,349-ton Yonakuni's stern at around 9:15 am in waters some 12 km north-northwest of Huangweiyu islet, and again collided with another Japanese patrol boat, Mizuki, 40 minutes later, Mainichi Daily News reported, citing the Japan Coast Guard (JCG).

Nobody was hurt from either vessel, and no fuel leaks had been reported.

The Chinese ship then left the area, a Japanese embassy official, who refused to be named, told China Daily.

But the Kyodo News Agency reported the JCG had announced an arrest warrant for the Chinese captain for what they described as disturbing law enforcement

What actually happened remained sketchy, with Phoenix TV quoting Wu Tianzhu, the owner of the trawler as saying that his 37-meter vessel did not hit the Japanese patrol boats, which were much larger in size.