Uganda is holding the 39-year-old chief of the Democratic Republic of Congo's M23 rebel movement, Sultani Makenga, after he surrendered to officials.

"I can confirm to you he [Makenga] is with us," an unnamed senior officer told the Reuters news agency.

"He surrendered to us yesterday and we're holding him somewhere and some other commanders of his," he added, saying those being held would remain at an undisclosed location until a peace agreement between the government and the M23 was signed.

"We have roughly about 1,500 M23 combatants who surrendered to us. We have disarmed all of them and we're in the process of documenting and categorising all their weapons," said Captain Ronal Kakurungu, an army spokesperson for Uganda's Western region.

The Congolese government had no immediate comment about the announcement.

The chief's whereabouts were unknown since Tuesday's announcement by the M23 that it was ceasing a 20-month insurgency in eastern DRC. Local officials worried he could have been in hiding with plans to regroup.

His surrender is a major coup for the Congolese army, which is backed by UN troops.

Makenga is on both UN and US sanctions lists after being accused of participating in several massacres, mutilations, abductions and sexual violence, including on children.

The leader of the former insurgents and his fellow M23 officers are considered "among the worst perpetrators of human rights violations in the DRC, or in the world for that matter," by the United Nations High Commissioner for Human Rights, Navi Pillay.

"Many of them may have been responsible for war crimes," Pillay said in June last year, appealing for them to face justice.

jlw/jm (dpa, Reuters, AP, AFP)