DHARAMSHALA, August 20: In a sharp contrast to the brutal treatment meted out to Tibetan peaceful protesters, China has over the weekend allowed thousands of Chinese to carry out anti-Japanese protests, even as some of the demonstrations turned violent.

Anti-Japanese demonstrations spread to more than 20 cities in China Sunday with demonstrators smashing Japan-made cars, vandalising Sushi restaurants and Japanese-owned businesses and trampling on miniature mannequins of Japanese soldiers dressed in World War II uniforms.

Japan's Kyodo news agency said some 5,000 people participated in protests in Shenzhen in southern Guangdong province, while a march in Chengdu was said to have drawn more than 2,000 people. China’s state news agency Xinhua reported that more than 1,000 protestors in Shandong's coastal city of Qingdao marched to the Consulate-General of Japan and another protest in the northeast city Shenyang also targeted Japan's consulate.

The protesters waved Chinese flags and called on Beijing to defend the country's territorial claims on the chain of uninhabited islands known as the Diaoyu in China and the Senkakus in Japan. The islands are controlled by Japan.

Demonstrators chanted “Diaoyu belongs to China. Get rid of Japanese militarism.” “Defend the Diaoyu Islands to the death,” one banner said. Another said, “Even if China is covered with graves, we must kill all Japanese.” Another photograph showed a handwritten sign taped to the entrance of Suning, a popular electronics store, telling customers it was no longer selling Japanese products.

Major international media outlets based in China reported that the demonstrations “appeared to be sanctioned and chaperoned” by the police, who have neither “prevented, suppressed or broken up” the gatherings.

China generally prohibits public protests or at least contains demonstrations that suit the needs of the Communist Party, fearing that they might spiral out of control or turn into popular antigovernment sentiment.

The protests were prompted by Japan’s arrest and deportation of Chinese “activists” who last week landed on the Senkaku islands and planted a Chinese flag.

Tensions intensified Sunday morning with news of about 10 Japanese activists, including local assembly members from Tokyo, swimming ashore to the disputed island, Uotsuri.

The group said they were responding to the pro-China activists’ landing, and they urged Prime Minister Yoshihiko Noda to do more to defend the islands.

In China, Global Times, a newspaper owned by People’s Daily, the Communist Party mouthpiece, held an impromptu seminar yesterday, with many participants calling for more radical action.

During the seminar, Maj. Gen. Luo Yuan called on China to send 100 boats to defend the islands.

“If necessary, we could make the Diaoyu Islands a target range for China’s Air Force and plant mines around them,” he said, according to a microblog posting by the newspaper.

A Chinese colonel, Dai Xu, a professor at the National Defense University, said the dispute offers “a good opportunity for us to build up our authority over the East China Sea.” He called for “a full-scale media war against the Japanese.”

Along with important fishing grounds, the disputed areas of the East China Sea are thought to hold potentially vast reserves of natural gas as well as smaller oil reserves. The U.S. Energy Information Administration cites Chinese oil companies saying contested areas of the East China Sea holds more than 20 million barrels of oil in reserves and reserves of natural gas at around 17.5 trillion cubic feet.

China is also embroiled in spats with Vietnam and the Philippines over the oil-rich South China Sea.