China moved to tamp down rising anti-Japan sentiment after a weekend of sometimes violent demonstrations, threatening Monday to arrest lawbreakers and scrubbing websites of protest-related images and posts.
But Japanese businesses were taking no chances, with restaurants and shops in Beijing, including popular clothing retailer Uniqlo, closed on Monday. Factories belonging to electronics maker Panasonic, two of which were damaged over the weekend, also were shut.
More demonstrations were expected Tuesday, the anniversary of a 1931 incident that Japan used as a pretext to invade Manchuria before World War II. Officials in at least one district of Beijing advised Japanese businesses not to open on Tuesday, Japan's Kyodo News agency reported.
Tensions have been growing for months in the dispute over ownership of a string of uninhabited islands in the East China Sea called the Senkaku in Japan and Diaoyu in China. Those came to a head last week when the Japanese government said it was purchasing some of the islands from their private owner to thwart a Japanese politician's plans to buy and develop them.
China reacted angrily, sending marine patrol ships inside Japanese-claimed waters around the islands, which Tokyo has administered since 1972. Some state media urged Chinese to show their patriotism by boycotting Japanese goods and canceling travel to Japan.
Protests flared in cities across China over the weekend, with occasional outbreaks of violence, including the torching and looting of Japanese-invested factories and shops. They were the largest anti-Japanese demonstrations since 2005, reflecting ever-present anger toward Tokyo that periodically bursts to the surface.
China's authoritarian government rarely allows protests and the wave of anti-Japanese demonstrations clearly received a degree of official approval. Chinese Foreign Ministry spokesman Hong Lei said Monday that Japan should be mindful of the Chinese public's feelings and return to the negotiating table.
"The Chinese people have expressed strong indignation," Hong told reporters at a regular briefing. "Whether the Japanese side can take seriously China's firm stance and the Chinese people's call for justice and whether they can take the correct attitude and action will determine how the situation develops."
Authorities, however, are walking a tightrope between allowing citizens to vent and losing control of the protests, which could then turn against the government.
By Monday, authorities were clamping down.
In the western city of Xi'an, police issued an order banning large-scale protests in commercial areas, districts with large populations, and anywhere near government offices. The statement also warned that the use of mobile texting or online messaging to organize illegal demonstrations was forbidden.
In the southern city of Guangzhou, police said they arrested seven people for attacking cars and three for vandalizing shops.
"The Guangzhou police would like to remind the public to be rational while being patriotic. Demonstrations must proceed according to law," police said in a statement.
Police in the eastern port of Qingdao, where protesters torched a Panasonic factory and Toyota dealership, also reported arrests.
Authorities also tried to rein in online sentiment, with searches for posts or images related to the demonstrations met with an error message on China's Twitter-like Sina Weibo microblogging site. Users who posted related content saw their material deleted by censors.
The tightened security follows demands from Japan that China ensure the safety of Japanese citizens and businesses. Japanese media have reported at least six incidents of Japanese citizens being attacked.
About 60 people protested Monday outside the Japanese Embassy in Beijing, far outnumbered by around 1,000 security personnel.
However, the end of the annual East China Sea fishing ban could raise new frictions. Thousands of fishing boats left ports on Sunday, many of them headed for waters near the disputed islands.
Protests were expected Tuesday in a number of cities to mark the anniversary of the Mukden Incident, the bombing of a railway in northeastern China in 1931 that was staged by Japan for a pretext to invade.
Meanwhile, state media moved to temper its rhetoric.
On Monday, the Beijing Morning Post, the Global Times and other state newspapers warned against irrational displays of patriotism and violence.
"Violent protests should never be condoned," the Global Times said in an online commentary. "Violence can only weaken the current campaign against Japan."