Ugandan traditional king Omusinga wa Rwenzururu Charles Wesley Mumbere was arrested Sunday following fresh clashes in the Rwenzori region
He was reportedly picked up from his Buhikira Royal Palace in Kasese town by the Uganda People's Defence Forces (UPDF) in a joint operation with police.
Mr Mubere was later airlifted to Kampala.
His arrest came just hours after police said at least 55 people were killed in fierce fighting that erupted in western Uganda between security forces and a separatist militia.
Police spokesman Andrew Felix Kaweesi said 14 police officers and 41 militants had died in the clashes on Saturday, when fighters linked to the royal guard of the Rwenzururu kingdom attacked patrolling security forces.
"Yesterday a joint Uganda police and UPDF (army) operation, patrolling in Kasese town... came under attack by Royal Guards of the kingdom. The attackers threw an improvised grenade which exploded and injured one soldier. Security forces reacted and shot in self-defence, killing four attackers," said Mr Kaweesi.
"That incident set of an explosion in all local sub-counties. Fighting continued from morning to late evening."
Mr Kaweesi said the attackers -- not all of who were royal guards -- had guns, spears and improvised explosive devices.