The wanted deputy of Uganda's murderous Lord's Resistance Army rebels, Okot Odhiambo, may have been killed in recent fighting, the Ugandan defence minister told AFP Friday.

Odhiambo was indicted by the Hague-based International Criminal Court (ICC) in 2005 along with LRA chief Joseph Kony and fellow rebel Dominic Ongwen on charges of butchering and kidnapping civilians.

"There are pointers from defectors that Okot Odhiambo may be dead," Defence Minister Crispus Kiyonga told AFP Friday. "Our forces are verifying these reports to check if indeed he died in the battles we have had with them and a position will be communicated."

"It will not be a surprise that he could be dead because the UPDF (Ugandan army) has in the past killed many top LRA commanders and he cannot be an exception," he added.

"The LRA's strength has diminished and the remaining force, including Kony, are on the run."

In recent years the group, a militant outfit whose doctrine mixes African mysticism with Christian extremism -- has been forced out of Uganda and Odhiambo had been thought to be hiding out with a hardcore of fighters in the remote jungles of Central African Republic, northeast Democratic Republic of Congo or South Sudan.

The United States has a unit of Special Forces soldiers helping in the hunt for LRA leaders.

In Washington, William Stevens, spokesman at the State Department's Bureau for African Affairs, said that US officials were "aware of reports" of Odhiambo's killing, but referred any questions to Ugandan and African Union officials.

Ugandan army spokesman Paddy Ankunda told AFP the intelligence reports had come from rebel defectors, who said the rebel commander may have died in a Ugandan army assault "at the end of last year", but gave no details on where the clash took place.

"We are trying to verify the report, but there is a very high possibility that he is dead," Ankunda said.

- 'Ruthless killer' -

According to the ICC warrant, former LRA members describe Odhiambo as a "ruthless killer" and "the one who killed the most".

Odhiambo is widely suspected to have directed the killing of some 300 civilians during a February 2004 attack on the Barlonyo internally displaced persons camp in northern Uganda, one of the single largest massacres in the LRA's brutal history.

After Odhiambo reportedly ordered the rebels to "kill every living thing", witnesses say camp residents were burnt alive in their homes, hacked to death with machetes, stabbed, bludgeoned and shot as they tried to escape.

An AFP reporter who met Odhiambo in 2005 described a slender and unsmiling man, dressed in neatly ironed military fatigues and the rebel's standard issue rubber boots, always flanked by heavily armed teenage soldiers and who would hold the gaze of those around without blinking.

Described as having "greying" hair by Interpol, Odhiambo ascended to the number-two position in the LRA in October of 2007, after Kony is thought to have ordered the killing of his previous deputy, ICC fugitive Vincent Otti.

Odhiambo is suspected to have played a central role in Otti's murder, and as Kony's loyal right-hand man serves as a vital go-between for different commanders spread out in the jungle.

Odhiambo's death "would be a historic blow to the LRA's command structure," the State Department's Stevens told AFP.

"It is clear that, despite the regional challenges, the AU Regional Task Force (AU-RTF) continues to make great strides toward ending the LRA threat. We congratulate the AU-RTF and especially the Ugandan military on their continued success in pursuing the LRA's remaining leaders and promoting defections."

Stevens said that Washington believes "it is critical that pressure continue to be put on the LRA to prevent it from regrouping," and called on the remaining fighters "to follow the lead of the over 100 individuals who have left the LRA since 2012 and put down their arms and return home."