At least 136 people were killed in tribal clashes in Sudan\'s Darfur region, a local official told Xinhua Tuesday \"Clashes broke out on Monday between Miseria and Al-Salamat tribes in Central Darfur state,\" said Ahmed Abdul-Rahman Al- Dikhairi, an administrator of Miseria tribe. \"108 members of Al-Salamt tribe and 28 members of Miseria tribe were killed during the clashes,\" he added. Sudan\'s security situation, already troubled by rebel insurgency, is increasingly compounded by inter-tribal fighting, which causes heavy casualties.