Colonel Felix Kulayigye said the bodyguard, a rebel commander known only as Binani, was killed in an engagement 175 miles north of Djema, a base in the Central African Republic where Uganda-led African Union (AU) troops are being advised by US special forces.
It was not clear if Kony, a self-styled mystic who has eluded capture for more than two decades, was part of the group of rebels that fled the attack in which Binani was killed.
“He was a member of the LRA high command,” Col Kulayigye said of Binani. “He was Kony’s chief bodyguard and he was also the LRA’s main logistician.”
Kony, whose rebellion originated in Uganda before spreading to other parts of Central Africa, was indicted by the International Criminal Court in 2005 for war crimes and crimes against humanity.
Last year, he became the focus of international attention after advocacy group Invisible Children released an online video highlighting LRA crimes and calling for Kony to be stopped from recruiting children.
Ugandan officials believe Kony may be hiding in a place called Kafia Kingi, along the volatile Sudan-South Sudan border.
The LRA, which used to have several thousand men, is now seriously degraded and scattered in small numbers in Congo, South Sudan and the Central African Republic. Only about 200 LRA rebels are still active in the jungle, according to the Ugandan military, but they can conduct hit-and-run operations that terrorise villagers.
About 2,500 AU troops hunting for Kony and other LRA commanders are being assisted by 100 US military advisers.