The Beijing headquarters of the Hong Kong-registered China Federation for Defending the Diaoyu Islands has been raided and some office equipment taken away, an activist says. Writer Yang Maodong also said Beijing police refused to accept his application for permission to organise a march, on the grounds that he was not a resident of the capital. The march was to commemorate the May Fourth Movement, the first mass movement in modern Chinese history, which opposed the Versailles Conference ruling that handed German concessions in Shandong to Japan after the end of the first world war. Yang, a graduate in philosophy from Shanghai's Huadong Normal University, said authorities raided the federation's office on Saturday and took away three computers and a printer. He said he and other activists had been shocked by the action and had appealed to the authorities to return the equipment and apologise. The federation was formed to apply to the central government for the right to develop the Diaoyu Islands through tourism, exploration and other commercial activities, Yang said. It was registered in Hong Kong in November. He also said that recent mainland protests opposing Japan's campaign for a permanent seat on the United Nations Security Council were 'indirect, peaceful and interactive' in nature and should not be stopped. 'The people are exercising their legal rights to assemble and protest and this should not be suppressed because they serve to uphold the country's sovereign rights externally and Chinese people's human rights internally,' he said.