US President Barack Obama said Friday he is sending 100 combat troops to central Africa to help and advise forces battling Ugandan Lord's Resistance Army rebels accused of rape, murder and kidnapping.

The US troops, subject to the approval of national authorities, could deploy in Uganda, South Sudan, the Central African Republic and Democratic Republic of the Congo, Obama said in a message to Congress.

LRA rebels are accused of terrorizing, murdering, raping and kidnapping thousands of people in the four nations, and tens of thousands of people died in their 20-year war with security forces in northern Uganda.

"These forces will act as advisors to partner forces that have the goal of removing from the battlefield Joseph Kony and other senior leadership of the LRA," Obama said, but warned they would not lead the fighting themselves.

"Although the US forces are combat-equipped, they will only be providing information, advice, and assistance to partner nation forces.

"They will not themselves engage LRA forces unless necessary for self-defense. All appropriate precautions have been taken to ensure the safety of US military personnel during their deployment."

The president said a small group of troops deployed on Wednesday and that additional forces will deploy over the next month.

Kony, accused of war crimes and wanted by the International Criminal Court, appears to have dropped any national political agenda and in recent years his marauding troops have sown death and destruction in the region.

The civil war effectively ended in 2006 when a peace process was launched, but Kony and his top commanders continue to commit atrocities in remote areas of neighboring countries.

General Carter Ham, the head of US Africa Command, said last week that his best estimate was that Kony was probably in the Central African Republic.

Obama said in his message that the LRA had "murdered, raped, and kidnapped tens of thousands of men, women, and children in central Africa."

"The LRA continues to commit atrocities across the Central African Republic, the Democratic Republic of the Congo, and South Sudan that have a disproportionate impact on regional security," he said.

In 2009, the US Congress enacted a law expressing support for increased US efforts to mitigate and eliminate the threat posed to civilians by the LRA.

And a year ago, Obama presented Congress with a plan to disarm the Lord's Resistance Army.

The scheme was meant to promote the "defection, disarmament, demobilization, and reintegration of remaining LRA fighters; and... increase humanitarian access and provide continued relief to affected communities."