sentences:  In response, security forces supported by Buddhist militia launched a "clearance operation" that has killed at least 1,000 people and forced more than 500,000 to flee their homes.The UN's top human rights official said on 11 September that the military's response was "clearly disproportionate" to insurgent attacks and warned that Myanmar's treatment of its Rohingya minority appears to be a "textbook example" of ethnic cleansing.Refugees have spoken of massacres in villages, where they say soldiers raided and burned their homes.