In recent years , particularly violent clashes broke out Process_start in 1993 between Jikany Nuer and Lou Nuer in Upper Nile , in 2009-2012 between Lou Nuer and Murle in Jonglei and in 2013-2014 between Maalia , Rizeigat , Messiria , Salamat and Bani Hussein in Darfur and West Kordofan .