Uganda’s military has confirmed that a senior commander in the rebel Lord’s Resistance Army (LRA) movement has been taken into custody by US forces.
The army spokesman told the BBC that soldiers had visited Dominic Ongwen, who surrendered in the Central African Republic, to formally identify him.
The International Criminal Court (ICC) wants to put Mr Ongwen on trial for war crimes and crimes against humanity.
But the Ugandan government has said it would prefer to try him at home.
Government spokesman Ofwono Opondo told the BBC that Mr Ongwen should be in Uganda by the end of the week, when he would be charged.
The LRA has abducted thousands of children in northern Uganda, and neighbouring countries, forcing the boys to become fighters and the girls to become sex slaves.
The US first deployed about 100 special forces in 2011 to support thousands of African troops searching for LRA commanders.
Dominic Ongwen is considered by some to be a deputy commander to LRA chief Joseph Kony.
Who Is Dominic Ongwen?
- Said to have been abducted by LRA, aged 10, as he walked to school in northern Uganda.
- Rose to become a top commander.
- Accused of crimes against humanity, including enslavement.
- ICC issued arrest warrant in 2005.
- Rumoured to have been killed in the same year.
- US offered $5m (£3.3m) reward for information leading to his arrest in 2013.
Earlier, US State Department spokeswoman Jen Psaki said that when the man surrendered to US forces he said was an LRA defector.
“If the individual proves to be Ongwen, his defection would represent a historic blow to the LRA’s command structure,” she told reporters in Washington.
Ugandan army spokesman Lt Col Paddy Ankunda told the BBC that Ugandan soldiers had confirmed Mr Ongwen’s identity after visiting him in the town of Obbo in the east of the Central African Republic (CAR).
Although Uganda would prefer Mr Ongwen to face justice at home, the government spokesman said it would liaise with the ICC, the African Union and UN on where the case would be heard.
Uganda’s President Yoweri Museveni has been very critical of the ICC recently, accusing it of unfairly targeting African leaders.
He had originally asked the ICC to investigate the LRA.
Mr Ongwen, who claims he joined the rebels’ ranks when snatched as a child, is said to have commanded the Sinia Brigade which has been blamed for some of the worst atrocities the group carried out in northern Uganda, where the LRA began its rebellion more than two decades ago.
Its estimated 200-500 fighters have since terrorised large swathes of the Democratic Republic of Congo, South Sudan and the CAR.
Joseph Kony has said the LRA is fighting to install a government in Uganda based on the Biblical Ten Commandments.
In 2013 the US offered a reward of up to $5m (£3.3m) for information leading to the arrest or capture of Joseph Kony, Dominic Ongwen and another LRA leader, Okot Odhiambo – all indicted by the ICC.
Then, in March last year, the US announced it was sending military aircraft and more special forces to help track down the LRA leadership.