Tribal violence and rebel-government battles have displaced at least 460,000 people in Sudan's Darfur this year, the United Nations said on Thursday, as violence worsens in the western region. "According to humanitarian organisations, so far in 2013 at least 460,000 people have fled their homes in Darfur as a result of inter-tribal fighting and clashes between the SAF (Sudanese army) and armed movements," the UN Office for the Coordination of Humanitarian Affairs (OCHA) said in its weekly bulletin.