The Khmer Rouge also classified by religion and ethnic group. They banned all religion and dispersed minority groups, forbidding them to speak their languages or to practice their customs. They especially targeted Buddhist monks, Muslims, Western-educated intellectuals, educated people in general, people who had contact with Western countries or with Vietnam, disabled people, and the ethnic Chinese, Laotians and Vietnamese. Some were put in the S-21 camp for interrogation involving torture in cases where a confession was useful to the government. Many others were summarily executed. Confessions forced at S-21 were extracted from prisoners through such methods as raising prisoners by their arms tied behind and dislocating shoulders, removing toenails with pliers, suffocating a prisoner repeatedly, and skinning a person while alive.[citation needed]

People were treated as opponents based on their appearance or background. Torture was widespread. In some instances, throats were slit as prisoners were tied to metal bed frames.
Thousands of politicians and bureaucrats accused of association with previous governments were executed. Phnom Penh was turned into a ghost city, while people in the countryside were dying of starvation or illnesses or simply killed.

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