Fighting between police and forces loyal to a tribal king have left at least 87 dead in western Uganda.

Police stormed the palace of King Charles Wesley Mumbere over the weekend in a government sanctioned attempt to arrest the tribal ruler. This led to a violent confrontation between police forces and Mumbere’s royal guard armed with spears and machetes, in addition to modern weapons.

Figures released by a police spokesman on Sunday placed the death toll at 16 police officers and 46 royal guards. 139 guards were also arrested. Bodies found on Monday however have raised the death toll to at least 87, according to the district police commander. King Mumbere was also arrested and has been charged with a murder unrelated to the weekend attack.

Mumbere is one of many tribal rulers in Uganda who are recognised by the constitution but hold no real authority and do not have official armies of their own. He had previously supported current President Yoweri Museveni’s opposition in the lead up to this year’s election in February, and after Museveni’s win, there were numerous clashes between King Mumbere’s supporters and security officials. Following this, President Museveni labelled these supporters as separatists and vowed to defeat them.

King Mumbere is the ruler of the Rwenzori region near Uganda’s border with the Democratic Republic of the Congo.  There has been a long simmering conflict between the central government and the kingdom, which feels that it has been marginalised.

Authorities have accused the Rwenzori royal guard of training with separatists in the mountains to attack government installations. King Mumbere has also been alleged to be seeking to turn the Rwenzori region into an independent state. The President expressly stated earlier this year however that any attempts to secede from Uganda by any region would not be tolerated.

This recent attack on Mumbere’s palace has however been condemned by human rights group Amnesty International. They have stated that the Ugandan government and security forces “must not jettison human rights in their handling of the clashes”. They have claimed that the police’s violence against Mumbere’s militia was a massacre, and that police were carrying out extra-judicial killings. They have said that many people appear to have been shot dead, and then had their bodies dumped.

The group has also stated that video footage broadcast by Ugandan TV stations showed bodies being dumped on river banks and in bushes, as well as people writhing in pain being thrown off the back of trucks with their hands tied behind their backs.

The Ugandan government has rejected these claims, with Jeje Odongo, Uganda’s internal minister, stating that security forces were acting in self-defence after they were supposedly attacked, and had to protect themselves.

King Mumbere, now in government custody, has denied any involvement in the violence.