Alexander F. Yuan/Associated Press
BEIJING — Anti-Japanese demonstrators took to the streets again on Sunday in cities across China, with the government offering mixed signals on whether it would continue to tolerate the sometimes violent outbursts.
The protests were orderly in Beijing, with several hundred people circling in front of the Japanese Embassy demanding Chinese control over a small island group known as Senkaku in Japan and as Diaoyu in China. Protests were also reported in other cities, including Shanghai, Guangzhou and Qingdao.
On Saturday, protests occurred in more than 50 cities, with some violence reported. A factory for the Panasonic Corporation was set on fire in Qingdao, and a Toyota dealership was looted, according to photographs posted on social media sites and local residents reached by telephone.
“Across China, calls have grown for boycotts of Japanese products. Many Japanese retailers and restaurants have been forced to place signs in their windows supporting China, and on Sunday, Japan’s prime minister, Yoshihiko Noda, asked China to protect Japanese and their property.
A signed editorial on the Web site of People’s Daily, the authoritative Communist Party newspaper, said the protests should be viewed sympathetically. While it did not defend the violence, the editorial said the protests were a symbol of the Chinese people’s patriotism.
“No one would doubt the pulses of patriotic fervor when the motherland is bullied,” the editorial said. “No one would fail to understand the compatriots’ hatred and fights when the country is provoked; because a people that has no guts and courage is doomed to be bullied, and a country that always hides low and bides its time will always come under attack.”
Some articles in the Chinese news media, however, said the protests should be “rational” and peaceful.
Defense Secretary Leon E. Panetta is scheduled to visit Beijing on Monday, and some observers said the government might try to limit the protests.
Just before landing in Tokyo on Sunday, Mr. Panetta told correspondents aboard his jet that he was worried that territorial disputes in the Pacific raise “the possibility that a misjudgment on one side or the other could result in violence.”
Mr. Panetta said the United States was not taking sides in any of the region’s territorial disagreements, but advocated diplomacy to peacefully resolve them. One option, he said, would be for the feuding nations to follow a code of conduct advocated by the Association of Southeast Asian Nations.
Both China and Japan claim the disputed islands, although Japan has controlled them for over a century. China increased its pressure on Japan after the Japanese government purchased the islands from private owners. Japan says the move was to prevent nationalists from using the islands, but China has seen it as a step to solidify Japanese control. In response, China dispatched surveillance ships to the waters near the islands.
Complicating the diplomatic dispute, Japan’s newly appointed ambassador to China, Shinichi Nishimiya, died Sunday after falling ill last week in Tokyo, according to Japanese and Chinese news reports. He was appointed ambassador last week and was to assume his duties next month.
China’s state-run news media has made repeated calls for the islands to be given to China, which claims that it controlled them before Japan’s colonial expansion in the late 19th century. Both China and Japan are also involved in territorial disputes with other countries over separate island chains, some of which are thought to be surrounded by rich deposits of natural resources in the surrounding waters.
There was evidence on Sunday that some Chinese government officials were involved in the protests. In the western city of Xi’an, activists on the Internet identified one of the officials as the police chief.
The political analyst Li Weidong said the official tolerance fit a longstanding pattern of behavior in which the Chinese government uses mass protests to further its foreign policy goals. In a text message sent to friends and associates, Mr. Li compared the current protesters to the Boxers, a quasi-religious group that was used by the Qing dynasty to oppose foreign incursions in the late 19th and early 20th centuries.
“Beijing dares not to fight, but it’s unable to talk it over either,” Mr. Li wrote. “So it has to employ Boxers, using product boycott to press Japan.”