Rights groups are urging Ugandan security forces to show restraint as they crack down on a tribal militia in a remote area near Congo.

More than four dozen people have been killed in clashes since Thursday, most of them guards protecting a tribal king who is critical of long-time President Yoweri Museveni. The militia, armed with modern weapons as well as spears and machetes, have killed more than a dozen police officers.

In a statement Monday, Amnesty International said the Ugandan security forces "must not jettison human rights in their handling of the clashes" in the western Kasese district.

Maria Burnett, an Africa researcher with Human Rights Watch, said that "everyone, including government troops and their commanders should face investigations into their conduct that led to the deaths."