Uganda ? Rioters angry over political and land issues clashed with government forces for a second day Friday, and at least six people were killed in Uganda’s capital and an outlying area.

The violence, which has killed a total of 13 people since Thursday, stems from disputes between the government and members of the Buganda, one of Uganda’s four ancient kingdoms. Members of the Buganda ethnic group have clashed previously with the government over land rights.

Barricades of burning tires were erected in Kampala as stone-throwing mobs roamed the streets, underlining growing tensions in a nation hailed for its relative stability and economic growth.

Some unemployed people also reportedly joined the rioting.

The possibility that the violence will continue today increased after police said they would prevent Buganda King Ronald Muwenda Mutebi II from traveling to a political rally. The government’s refusal to allow the trip on security grounds sparked the first day of rioting Thursday, with the king’s supporters insisting he should be allowed to move freely.