Ten Japanese nationalists who planted flags on a remote island have caused a wave of furious protest across China, because the sovereignty of the islands is disputed.

The subject of the rage is five uninhabited islets and three barren rocks, 120 miles northeast of Taiwan.

The islands, known as the Diaoyu Islands in China and the Senkaku Retto in Japan, are technically Japanese - the territory was transferred to the Japanese in 1971 - but China disputes this, claiming the islands have been Chinese for many centuries previously.

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An anti-Japan protester holds a poster which reads "Declare War on Japan" in Hangzhou, in eastern China's Zhejiang province

Members of Gambare Nippon, Japanese nationalists, swum ashore from a protest flotilla on Saturday, planting the red and white Rising Sun flag on the island.

They were responding to 14 Hong Kong protesters, who were arrested after trying to plant a Chinese flag on the island earlier this week.

The Chinese protesters will be deported, but will not be prosecuted in Japan, Tokyo has promised.

Tokyo politician Eiji Kosaka told the Agence France Presse: "This is undoubtedly Japanese territory. On the mountain we found Japanese-style houses that had places for drying fish.

"It is very sad that the Japanese government is doing nothing with these islands."

Armed police were called in across China to quell angry anti-Japanese demonstrations.

Crowds of up to 3000 gathered in Shenzhen, Hangzhou, Hong Kong, Guangzhou, Shenyang, Harbin, Qingdao and Chengdu, with Japanese flags set alight and Chinese media said Japanese restaurants and cars had been targeted.

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Japanese activists hold the national flags on Uotsuri island, one of the islands of Senkaku in Japanese and Diaoyu in Chinese, in East China Sea

Tensions in the region have been close to boiling point this week, which saw the anniversary of Japan's World War II surrender.

Japan has apparently sought to buy more islands in the disputed area -which currently belong to a private individual, a move China believes is unlawful.

Japanese media reported that the country's ambassador to China is in the process of being replaced, after he criticised the proposal to purchase the islands.

The islands look unimpressive at first glance, but China, Taiwan and Japan all want control of the territory for defensive purposes, and for the rich mineral and oil deposits under them.

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  • Chinese look at overturned Japanese cars after an anti-Japan protest in Shenzhen, China's Guangdong Province, Sunday, Aug. 19, 2012. Japanese activists swam ashore and raised flags Sunday on an island claimed by both Japan and China, fanning an escalating territorial dispute between the two Asian powers. (AP Photo/Vincent Yu)

  • Chinese look at overturned Japanese cars after an anti-Japan protest in Shenzhen, China's Guangdong Province, Sunday, Aug. 19, 2012. Japanese activists swam ashore and raised flags Sunday on an island claimed by both Japan and China, fanning an escalating territorial dispute between the two Asian powers. (AP Photo/Vincent Yu)

  • Anti-Japan protesters march with Chinese national flags and banners, one on the right reads "Diaoyu Islands belong to China", in Hangzhou, in eastern China's Zhejiang province, Sunday, Aug. 19, 2012. Japanese activists swam ashore and raised flags Sunday on an island claimed by both Japan and China, fanning an escalating territorial dispute between the two Asian powers. (AP Photo) CHINA OUT

  • Anti-Japan protesters wave Chinese national flags while marching in Chengdu, in southwestern China's Sichuan province, Sunday Aug. 19, 2012. Japanese activists swam ashore and raised flags Sunday on an island claimed by both Japan and China, fanning an escalating territorial dispute between the two Asian powers. (AP Photo) CHINA OUT

  • Anti-Japan protesters shout slogans while marching outside Japanese Embassy with Chinese national flags and banners in Beijing, China, Sunday, Aug. 19, 2012. One of the banners reads "Diaoyu Islands belong to China since 1372! " A group of Japanese activists swam ashore and raised flags early Sunday on one of a group of islands at the center of an escalating territorial dispute with China. (AP Photo/Alexander F. Yuan)

  • Anti-Japan protesters shout slogans while marching with Chinese national flags and banners towards the Japanese Embassy in Beijing Saturday, Aug. 18, 2012. Japan on Friday expelled several Chinese who were arrested after they landed on disputed islands, but the activists vowed to take new trips there that could again inflame territorial tensions in North Asia. (AP Photo/Alexander F. Yuan)

  • Two anti-Japanese protesters, left, throw eggs towards the Japanese Embassy outside the embassy entrance in Beijing, China, Friday, Aug. 17, 2012. Japan has decided to deport 14 Chinese activists who were arrested this week for landing without authorization on disputed islands in the East China Sea. (AP Photo/Alexander F. Yuan)

  • Anti-Japan protesters with a placard reading "Down with Japanese militarism" tear mock Japanese Rising Sun Flags during a rally outside the Japanese Consulate General in Hong Kong Thursday Aug. 16, 2012. They demanded Japanese government to release Chinese activists arrested in Japan after landing on Uotsuri Island, one of the islands of Senkaku in Japanese and Diaoyu in Chinese. Japan is considering deporting 14 Chinese activists arrested for landing without authorization on disputed islands in the East China Sea, as harsh criticisms and repeated demands for their release erupted Thursday in China. (AP Photo/Kin Cheung)

  • An anti-Japan protester tears Japanese Rising Sun Flag during a rally outside the Japanese Consulate General in Hong Kong Thursday Aug. 16, 2012 as they demand Japanese government to release Chinese activists arrested in Japan after landing on Uotsuri Island, one of the islands of Senkaku in Japanese and Diaoyu in Chinese. Japan is considering deporting 14 Chinese activists arrested for landing without authorization on disputed islands in the East China Sea, as harsh criticisms and repeated demands for their release erupted Thursday in China. (AP Photo/Kin Cheung)

  • Anti-Japan protesters wear headband written "Protest" during a rally outside the Japanese Consulate General in Hong Kong Thursday Aug. 16, 2012 as they demand Japanese government to release Chinese activists arrested in Japan after landing on Uotsuri Island, one of the islands of Senkaku in Japanese and Diaoyu in Chinese. China's official Xinhua News Agency said the arrests of the 14 people, who included Hong Kong residents and mainland Chinese, had caused tensions over its territorial dispute with Japan to surge "to a new high." (AP Photo/Kin Cheung)

  • Protesters hold slogan reading "Diaoyu Island is Ours" during a protest in front of the Japanese government office in Taipei, Taiwan, Wednesday, Aug. 15, 2012. More than 100 Taiwanese gathered to protest what they say are Tokyo's plans to nationalize disputed islands also claimed by Taiwan and China. The islands called Senkaku in Japanese and Diaoyu in Chinese have long been a source of tension in the region. (AP Photo/Chiang Ying-ying)