Academic discourse considers both genocide and ethnic cleansing to exist 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, racial, religious, or national group. Some academics consider genocide as a subset of "murderous ethnic cleansing". Thus, these concepts are different, but related, as Norman Naimark writes: "literally and figuratively, ethnic cleansing bleeds into genocide, as mass murder is committed in order to rid the land of a people"