The only mainlander to set foot on the disputed Diaoyu Islands during the protest sail from Hong Kong in August was taken from his Shenzhen home by police and detained for 15 hours, a leading Hong Kong activist confirmed yesterday. Shenzhen security personnel plucked Fang Xiaosong and three housemates from their residence at 1am on Thursday and held Fang well into the afternoon for questioning, said Yang Kuang, the captain of the fishing boat that sailed to the Daioyus. Yang suspected Fang's detention was related to his recent efforts to set up a South China branch of the China Federation for Defending the Diaoyu Islands, the Hong Kong-based organisation to assert China's sovereignty over the islands. "[Fang] has done nothing wrong," Yang said. "What he [did] was very meaningful." Yang said Shenzhen authorities told him Fang's detention was a misunderstanding. Fang was one of seven activists to walk ashore on the main Diaoyu island on August 15 after a tense confrontation between their fishing boat, Kai Fung No2, and Japan Coast Guard vessels. The seven were held briefly before being deported by the Japanese, who control the islands. The activists were hailed as national heroes and inspired a wave of anti-Japanese protests on the mainland. The central government, however, has sent mixed signals to the activists, encouraging some protests but discouraging development of competing political organisations.