An investigation by Human Rights Watch detailed Thursday in a press statement said tribal elders and opposition party officials "planned and organized ethnic-based violence in the Rift Valley."
"We have evidence that ODM politicians and local leaders actively fomented some post-election violence, and the authorities should investigate and make sure it stops now," said Georgette Gagnon, acting Africa director at Human Rights Watch.
The group called on ODM members to take measures to stop further attacks and urged Kenyan police to deploy additional forces to the western Kenyan city of Eldoret and adjacent regions.
The investigation highlights testimony by numerous members of targeted communities accusing local elders and ODM officers of organizing "gangs of local youth" to loot and otherwise inflict violence upon the region.
Notable deaths of 2014 [PHOTOS]