The communist government did not bring peace in Cambodia. The Cambodian government regarded Vietnam and Thailand as aggressors. The hostile attitude against the Vietnam was particularly bad. The hostility grew more severe with the unification of Vietnam and with the communization of Cambodia.

Khmer Rouge announced a new constitution in January 1976 and changed the name of Cambodia to 'Democratic Kampuchea (DK)'. The new government was mostly under the Paris-educated leadership: Khieu Samphan as President of the State Presidium (Head of State), Pol Pot as Prime Minister, Ieng Sary as Deputy Prime Minister, Son Sen Defense Minster, and Nuon Chea as Chairman of the National Assembly.