Men and women may be imprisoned because of their political or religious beliefs or because of their colour or ethnic origin, although they have never used nor advocated violence. Most prisoners of conscience are detained for trying to exercise their rights of freedom of expression, association, assembly or movement. Some are held simply because of the political activity of members of their family. However, few governments admit that they detain people in violation of internationally agreed norms, and consequently treat prisoners of conscience as criminal offenders.