China's top AIDS activist, whose group helped uncover a major tainted blood-selling scandal in the 1990s, said Tuesday he had fled with his family to the United States because he feared for his safety. Wan Yanhai, 46, said he, his wife and his daughter were staying with friends in the eastern US city of Philadelphia after leaving China in recent days. "I have been living in fear, if I wasn't afraid then I wouldn't have left... I have no sense of personal safety," Wan told AFP by telephone. "There were a lot of pressures -- from the commerce and industry departments, the police, the tax authorities, the propaganda department, the education ministry." Wan's decision to leave highlights the increasing pressure felt by independent activists in China, who are under constant scrutiny by wary Communist officials. In recent months, the government has jailed several top dissidents, earning Western criticism. It has clamped down on non-governmental organisations, human rights lawyers, online citizen journalists and petitioners, rights groups say.