In 1975, the Khmer Republic collapsed after 119 days of offensives by the Communist troops. The Communist Party of Kampuchea (CPK; also known as the Khmer Rouge) started to reshape the country into a classless society by relocating the entire urban population into the countryside to work as farmers. However, the people who had previously been living in cities did not have the ability to cultivate land. As a result, malnutrition and hunger led to the death of hundreds of thousands of people. In their attempt to restructure the country, the CPK oppressed religion and abandoned industrial infrastructure. Businessmen and intellectuals were executed, and schools, hospitals, and banks were closed. Between 1.4 and 2.2 million Cambodians died under the rule of the Khmer Rouge. After the invasion of the country by Vietnamese forces and the Kampuchean United Front for National Salvation (KUFNS) in 1979, a decade of civil war followed. Only in 1991, a United Nations mandate to enforce ceasefire and disarmament marked the commencement of a peace and resettlement process that enabled free and fair elections for a constituent assembly in 1993.