A prisoner-of-war camp that Japanese forces in Liaoning used during the second world war is to be protected as an historical site. The camp will mark Japan's history of invasion in China - evidence that must be maintained, according to state media. he camp was used to intern allied forces held captive in Shenyang, capital of the northeastern province. Zhang Yibo, 76, chairman of a research organisation that focuses on the Japanese invasion of China, said: 'By preserving this site, we hope the Japanese government will admit to their history of invasion in China. We also want to put pressure on the American government to carefully handle their relations with Japan.' Most of the camp has been demolished and only three buildings, including one that housed Japanese guards and a clinic, are intact. A workshop about 1km from the camp was now a factory, state media said. But for the most part, it has retained its original appearance. Local government plans to shut the factory and relocate the tenants had proven difficult because of the number of poor residents living in the grounds, Professor Zhang said. His group has tried to lobby local government and relevant US organisations to establish a museum at the site. Last month a group of American POWs returned to make sure their role in the second world war would not be forgotten. According to Professor Zhang, about 1,500 POWs from the Pacific theatre were sent to the camp between November 1942 and July 1943. Prisoners were mostly US soldiers, including 18 high-ranking officers and one lieutenant-general. Nearly 27 per cent of the camp prisoners had died by August 1945, either from sickness or beatings, Xinhua reported.