A man claiming to be a senior commander in the notorious rebel movement the Lord's Resistance Army (LRA) has been taken into custody by US forces, media reported.
The man, who identified himself as Dominic Ongwen, surrendered in the Central African Republic (CAR), BBC reported citing US State Department as saying.
Ongwen is wanted by the International Criminal Court on suspicion of war crimes and crimes against humanity.
He is considered by some to be a deputy commander to LRA chief Joseph Kony.
US State Department spokesperson Jen Psaki said the man claimed he was an LRA defector.
"In co-ordination with the AURTF (African Union forces), US military forces took custody of an individual claiming to be a defector from the LRA. That individual later identified himself as Ongwen," she told reporters in Washington.
"Efforts to establish full and positive identification continue. If the individual proves to be Ongwen, his defection would represent a historic blow to the LRA's command structure."
Ongwen is said to have commanded the LRA's Sinia Brigade which has been blamed for some of the worst atrocities the group carried out in northern Uganda.
Joseph Kony and the LRA have waged war in Uganda and the region for more than two decades.
Joseph Kony's Lord's Resistance Army has spread fear across a wide area of central Africa.
He says the LRA is fighting to install a government in Uganda based on the Biblical Ten Commandments.
The group first emerged in Uganda but its estimated 200-500 fighters have terrorised large swathes of the Democratic Republic of Congo, South Sudan and the CAR.
Joseph Kony is wanted by the International Criminal Court for rape, mutilation and murder of civilians, as well as forcibly recruiting children to serve as soldiers and sex slaves.
Ongwen himself has claimed he was snatched by the LRA as a child.
The US first deployed about 100 special forces in 2011 to support thousands of African troops seeking the LRA leader.
In 2013 the US offered a reward of up to Five million dollars for information leading to the arrest or capture of Joseph Kony, Dominic Ongwen and another LRA leader, Okot Odhiambo.
Then, in March last year, the US announced it was sending military aircraft and more special forces to help track down the LRA leadership.
African Union-led forces have remained in charge of the operation, with the US supplying an advisory role.
