China has vowed to protect Japanese citizens and property as the authorities move to curb violent anti-Japanese protests across the country amid a major territorial standoff between Beijing and Tokyo, and ahead of a sensitive political anniversary.
Foreign ministry spokesman Hong Lei called on Chinese protesters to express themselves in an "orderly, rational, and lawful" manner.
"The Chinese people have expressed their united opposition to the illegal purchase of the Diaoyu Islands by Japan," Hong told a regular news briefing in Beijing.
"The gravely destructive consequences of Japan's illegal purchase of the Diaoyu Islands are steadily emerging, and the responsibility for this should be borne by Japan," Hong said.
The islands, called the Senkaku by Japan and Diaoyu by China, are also claimed by self-ruled Taiwan, which China considers a breakaway Chinese province.
Hong said the ball was now in Japan's court, calling on Tokyo to "mend its ways," following mass protests against Japan over the East China Sea islands.
A number of Japanese factories in China remained shuttered on Monday, with Japanese expatriates urged to stay indoors after rioters overturned Japanese cars and attacked Japanese-branded businesses.
Riot police in the southern city of Shenzhen fired tear gas and water cannons in a bid to control a crowd of more than 10,000 protesters that converged on the city's Futian district on Sunday, marching along a major road to government offices in Lo Wu district, near the immigration border with neighboring Hong Kong.
Many carried anti-Japanese signs and shouted slogans, witnesses said.
"There were protests all the way from Lo Wu to Nanshan district," said a Shenzhen resident surnamed Liang. "It was pretty serious ... in my view the most serious things have ever gotten."
"I was driving a Japanese car, but I'm not going to go anywhere in it other than to work and back," she said.
The protesters focused much of their anger on the Shenzhen branch of the Japanese department store Seibu, Hong Kong media reported, shouting "Go on, go on, smash glass and hurt someone," and attacking police who tried to intervene, detaining some of their number.
Some climbed onto the water cannon truck, while others overturned police vehicles amid shouts of "Smash, smash, smash!"
A small crowd of around 200 protesters remained outside the Japanese Embassy in Beijing on Monday, shouting slogans and waving banners, and occasionally throwing trash at the building, which was sealed off with iron barricades and guarded by police.
A resident of the embassy district surnamed Li said all the Japanese restaurants in the area were closed on Monday.
"They ... sealed off the road in the immediate vicinity of the embassy," she said. "There are definitely some people down there demonstrating, but not that many this morning."
"The supermarkets nearby are open, but a few of the restaurants have closed; the ones serving Japanese food," Li added. "They all have Chinese flags out front and signs saying 'We are all Chinese,' or 'Run by Chinese.'"
Police in Guangzhou detained 11 people over the weekend in connection with the protests on public order offenses, the municipal government said on its microblogging account, as Hong Kong media showed television coverage of similar clashes between protesters and police to those in Shenzhen.
"We encourage citizens to take photos and video of anyone engaging in illegal activities and to report them," the government statement said.
It called on citizens to express their patriotic feeling in "an orderly manner," warning that anyone crossing the line into criminal activity would only harm China's international image and play into the hands of its opponents.
An employee who answered the phone at Guangzhou's Japanese-invested Garden Hotel, which was surrounded by hundreds of angry protesters and smashed up on Sunday, said the management was still trying to assess the cost of the damage.
"Today, things are pretty much back to normal, and it's business as usual," she said.
She said the hotel hadn't taken extra security measures. "But I can't speak for the police," she added.
An official who answered the phone at the Guangzhou municipal government's propaganda department declined to comment on the extent of the damage.
"Maybe you could send us a letter requesting an interview," the official said. "We will get in touch with the relevant departments, and then supply you with the relevant figures."
Police in the northern city of Xian issued a ban on public gatherings anywhere within the city's ancient walls.
The municipal police department reported that there had been a number of incidences of "smashing, arson, and illegal activities," in recent days.
In the southwestern province of Sichuan, the authorities dispatched more than 200 armed police in full riot gear to guard two Japanese department stores in the provincial capital, Chengdu.
Meanwhile, hundreds of Chinese fishing vessels set out to join an activist vessel from Hong Kong on Monday in the waters near the islands, ahead of the sensitive anniversary of the "Sept. 18 incident," which came ahead of the Japanese invasion of northeastern China in 1931.
Beijing University of Science and Technology professor Hu Xingdou said the protests had highlighted a lack of channels through which people could express themselves.
"Chinese people have missed out on citizenship education and there are always some among them who are going to turn into perpetrators of violence," Hu said. "Patriotism is all too often a double-edged sword."
"It can also all too easily turn into extreme nationalism, which is against openness [to the outside world] and which targets foreigners in revenge attacks."
He said the legacy of the political violence of the Cultural Revolution (1966-1976) is still visible in today's society.
"Chinese people are either feudal vassals, or they are political thugs or warriors from the Cultural Revolution," Hu said. "They are irrational in their treatment of foreigners."
China's official media called on Japan to "stick to the promises it made and treaties it signed on the occasion of the country's surrender at the end of World War II."
The officially controlled English-language China Daily warned in an editorial that the ongoing territorial dispute would likely exacerbate public anger around the anniversary.
"The Japanese government should take note of mainstream Chinese public opinion, as voiced in those protests, and think twice about its illegal activities," the paper said.
Reported by Wen Yuqing and Lin Jing for RFA's Cantonese service, and by Qiao Long and Xin Yu for the Mandarin service. Translated and written in English by Luisetta Mudie.