An official statement said that he had 'left for medical treatment abroad'. Last night he was on his way to the United States, where his wife is studying at Columbia University, New York.
Mr Wang, 35, who is suffering from Hepatitis B and heart disease, was sentenced in February 1991 to 13 years' imprisonment and four years' deprivation of political rights on charges of 'conspiracy to subvert the government' and 'counter-revolutionary propaganda and incitement'. The other alleged 'black hand', Chen Ziming, was sentenced to 13 years and is still in jail.
Mr Wang's release comes at a time when Peking is nervous about the possibility of social unrest. June marks the fifth anniversary of the crack-down in the 1989 Tiananmen Square demonstrations, and military and public security patrols in the capital have been increased. His release may mean that Peking is concerned about reaction if he were to die in custody.
China is sending conflicting signals to Washington. Just two weeks ago, the Chinese authorities rearrested the country's best-known dissident, Wei Jingsheng, who was freed last autumn, immediately before the decision on whether Peking would host the Olympics in the year 2000.
President Clinton has stated that renewal of the MFN is tied to 'significant progress' in human rights in China, but the administration, under pressure from US businessmen, is believed to be searching for a face-saving way to extend China's trade privileges.
Mr Wang, son of a senior People's Liberation Army officer, was first jailed in 1976 for taking part in protests against the Gang of Four. During the Democracy Wall movement in the late Seventies, he was deputy editor of the unofficial journal, Beijing Spring.