Security is being tightened around Japanese diplomatic offices in China because of threats of demonstrations to protest Japan's detention of a Chinese boat captain. Peter Simpson reports from Beijing.
Chinese police Friday maintained a high profile around Japan's embassy in Beijing and other Japanese interests.
Japanese authorities have detained a Chinese fishing boat captain because of a collision between his boat and Japanese patrol boats near islands both Beijing and Tokyo claim.
The Japanese police are investigating whether charges should be filed against the captain.
The incident has created a diplomatic standoff, sparking scattered small protests this week in China. There have been reports that larger protests are expected Saturday.
Chinese Foreign Ministry spokeswoman Jiang Yu says China demands that Japan release the captain immediately.
Jiang says believe that Chinese public will express views in what she describes as a rational way.
She also says Japan started the dispute and should take full responsibility to resolve it.
The dispute centers on uninhabited islands - called the Senkaku in Japan and Diaoyu in China, surrounded by rich fishing grounds. The seabed around the islands also is believed to contain oil and gas deposits.
Both countries claim them, as does the island of Taiwan. In recent years, Chinese activists have seized on the issue as one of national pride.
There are fears the latest incident could set off a repeat of violent protests against Japanese interests in China in 2005 and 2006.
Adding to tensions this time is that Saturday marks the 79th anniversary of what China calls the September 18th Incident, when Japanese troops invaded. Japan's seizure of a large part of China before and during World War Two has left deep bitterness in the country.
Relations between China and Japan are often distrustful, but the countries have attempted in the past to contain tensions because of their close economic ties.
Some Chinese people say the dispute does not worry them.
Li Xin is Chinese man living in Japan, who is on a visit back to his native Beijing.
He says he is never troubled by such diplomatic arguments when in Japan and thinks most Chinese would rather have peace between the two nations.
Li says he says he cares for China and is proud to be Chinese but he and other ordinary citizens have little power over the relationship between the two nations.
He says the dispute is between politicians.
China's government is cautious about the strong nationalism that often accompanies anti-Japan sentiment. The governing Communist Party has repeatedly warned that social stability is key to the nation. Political analysts say Beijing is concerned that any protests could get out of hand and challenge the government.
At least one Chinese nationalist organization reported Friday that its Web site had been blocked. The organization has campaigned against Japan in the dispute over the islands, but its leaders say they did not play to hold a demonstration Saturday.