The forcible transfer of the population of specific groups has been a feature of state practice throughout recorded history. The Assyrian king Tiglath-Pileser is generally credited with carrying out the first known example when he forcefully removed one-half of the population from the land that he conquered. More recently, European colonial settlers in North America ‘ethnically cleansed’ the land of native Americans and other indigenous peoples. The 20th century was a particularly bloody era of forced population transfers and the practice was commonly referred to as ethnic cleansing.
The term is broadly defined and has come to refer to a policy of expulsion or removal of civilians from particular geographic areas and the destruction of property associated with a targeted group. Such measures may be used to create an area of ethnic purity within a state or to clear an entire region of ethnic or religious conflict (Mazowiecki Third Report I para. 11). It can be conducted both in times of armed conflict and peacetime.
Ethnic cleansing, however, does not imply an intention to destroy the targeted group and does not have to occur at all times of war or other armed conflict. Its occurrence, as well as the methods employed to carry it out, are prohibited under international law regardless of the circumstances in which they take place.
The term has been included in the UN’s list of crimes under the UN Charter and incorporated into the concept of the Responsibility to Protect. The ICJ has, however, confirmed that the act of ethnic cleansing is not an independent crime under international law but rather is subordinate to genocide, crimes against humanity and war crimes (Croatia v Serbia – Application of the Convention on the Prevention and Punishment of the Crime of Genocide Case, ICJ Rep., p. 24).