Amnesty International has accused Uganda of carrying out extrajudicial executions as authorities in the east African country said 62 people had died in clashes between a tribal militia and security forces in a restive western region.

The fighting between royal guards of a tribal king, Charles Wesley Mumbere, and a combined army and police force occurred on Saturday and Sunday in Kasese, the biggest town in Uganda’s Rwenzori region located near the border with the Democratic Republic of Congo.

Amnesty’s Halakhe has called on the government of Uganda to launch a thorough investigation into Kasese killings.

“Whatever the origin and source of the violence, the Ugandan security forces must not be allowed to jettison their human rights obligations,” Halakhe said.

“The government must ensure that police and soldiers observe restraint and desist from extrajudicial executions,” he added.

Halakhe said those suspected of unlawful killings and other crimes such as torture must be brought to justice in fair trials without recourse to the death penalty.

According to police figures, the bloodshed killed at least 46 members of the king’s guards and 16 police officers. Security forces also arrested 140 others, including King Charles Wesley Mumbere himself.

“The full picture of the weekend’s events is yet to emerge, but there appears to be shocking examples of unlawful killings and a complete disregard for human rights during the arrests,” Amnesty said.

“In a shocking display of heavy-handedness, many people appear to have been summarily shot dead and their bodies dumped,” Abdullahi Halakhe, Amnesty International’s East Africa researcher, said. He says video footage broadcast by Ugandan TV stations shows the bodies of young men apparently dumped on river banks and in bushes, and men writhing in pain as they are tossed off pickup trucks with their hands tied behind their backs.

Uganda’s main opposition leader Kizza Besigye shared gruesome images which appeared to show dozens of bodies piled up in front of the palace gates, condemning the “massacre.”

Ugandan authorities say the royal guards are part of a militia striving to establish an independent republic straddling Uganda and the neighboring Congo.

On Saturday, the army deployed a combined force to arrest the alleged separatist militia but faced strict resistance.

Authorities said Ugandan President Yoweri Museveni had called the king at least twice on Sunday morning and ordered him to rein in his guards but the king refused to do so.

“So we had no option, after that we had to storm the palace and get these terrorists, and that is what we did,” Brigadier Peter Elwelu of the Ugandan army said.

King Mumbere has strongly rejected having any links with the separatists.