KAMPALA , Uganda ( CNN ) -- At least 21 people were killed and more than 80 others injured during three days of rioting here last week , a police spokeswoman said Monday . Ugandan police ride past a burning barricade in the Natete suburb of Kampala on Friday . Police spokeswoman Judith Nabakooba said 663 people had been arrested and 86 people had been injured . President Yoweri Museveni is to address the violence in a speech to parliament slated for Tuesday afternoon . Though the mood on the streets in the capital city was calm Monday , tensions between Museveni and the Buganda kingdom -- headed by King Ronald Mutebi II , the ruler of the Baganda tribe -- have intensified in recent years . They erupted into violence last Thursday , when the government said it would not allow the king to travel to an area inhabited by a renegade rival group . Kings in the east African nation are limited to a ceremonial role overseeing traditional and cultural affairs . Government officials and the Buganda kingdom have been at odds for years , sparring over land , sovereignty and political power . After the travel ban , mostly young Bagandans took to the streets , stealing ammunition from a police station and confronting officers , accusing them of harassment . `` The government is wrong to undermine cultural institutions , which are the backbone of Uganda 's heritage , '' said Mzamiru Balidha , a resident of Kampala . `` Cultural leaders must be left alone since they are not interfering in politics . '' Rioters burned tires and cars , set buildings afire and looted stores . Streets in the capital were strewn with debris over the weekend , including torched cars and burned tires . By Sunday , police and the army were patrolling deserted streets as residents tried to return to normalcy after the protests . `` I 'm happy to see that there is peace now , '' said Harry Sagara of Kampala . `` Now people can return to work . '' A government official said Sunday that the two leaders have pledged to meet and address their differences . `` Both the central government and the king are still working out details of the meeting , '' said Daudi Migereko , the minister of parliamentary affairs . In Washington , the U.S. State Department cautioned Americans in Uganda about the potential for more violent demonstrations this week . `` U.S. citizens should be aware that even peaceful gatherings and demonstrations can turn unexpectedly violent , '' the State Department travel alert states . Bagandans are the dominant ethnic group and one of four ancient kingdoms in the nation . Journalist Samson Ntale in Kampala , Uganda , contributed to this report .
NEW : Ugandan president to address parliament Monday on deadly riots . NEW : Death toll from two days of rioting rises to 21 ; 86 ##0 , 000 arrested . U.S. embassy warns Americans in Uganda of potential threat of more violence . Rioting sparked by central government 's travel ban on a tribal king .