Ethnic cleansing is a purposeful policy designed by one ethnic or religious group to remove, by violent and terror-inspiring means, the civilian population of another ethnic or religious group from certain geographic areas. The term gained widespread acceptance by the 1990's in academic discourse; despite originally being used by the perpetrators during the Yugoslav Wars, the term is now considered "the widely accepted scholarly term used to describe the systematic and violent removal of undesired ethnic groups from a given territory." Ethnic cleansing is not to be confused with genocide; however, academic discourse considers both as existing in a spectrum of assaults on nations or religio-ethnic groups. Ethnic cleansing is similar to forced deportation or population transfer whereas genocide is the intentional murder of part or all of a particular ethnic, religious, or national group. The idea in ethnic cleansing is "to get people to move, and the means used to this end range from the legal to the semi-legal." Some academics consider genocide as a subset of "murderous ethnic cleansing." Thus, these concepts are different, but related, "literally and figuratively, ethnic cleansing bleeds into genocide, as mass murder is committed in order to rid the land of a people." .
The Kosovo War, was an armed conflict in the province of Kosovo, of the Federal Republic of Yugoslavia, fought between Yugoslav government forces and Albanian separatist forces (KLA), supported by NATO from 1998 to 1999. The KLA, formed in 1991, began attacking police stations and Yugoslav government offices in February 1996, which resulted in an increase in the number of Yugoslav security forces in the region. This led to an escalation into a conflict, although it was initially viewed as an insurgency. The KLA was regarded by the US as a terrorist group until 1998 when it was de-listed for classified reasons.