NEW : Ugandan president to address parliament Monday on deadly riots . The U.S. State Department said it was "deeply concerned" by the violence. Police spokeswoman Judith Nabakooba said 663 people had been arrested and 86 people had been injured . Death toll from three days of rioting rises to 21 ; 86 injured , 663 arrested . U.S. government warns Americans in Uganda of potential danger of more violence . Rioting sparked by central government 's travel ban on a tribal king .
NEW : Ugandan president to address parliament Monday on deadly riots . The U.S. State Department said it was "deeply concerned" by the violence. Death toll from three days of rioting rises to 21 ; 86 injured , 663 arrested . U.S. government warns Americans in Uganda of potential danger of more violence . Rioting sparked by central government 's travel ban on a tribal king .