KAMPALA, Uganda >> At least 1,700 Congolese M23 rebels, including the top commander, have surrendered to Ugandan authorities following their defeat by Congolese troops, a Ugandan military official said Thursday.

Gen. Sultani Makenga, M23’s military commander, and his fighters were being held by the Ugandan military in Mgahinga, a forested area near the Congo border, the official said. The rebels had been disarmed and were being registered by Ugandan officials, said the official, who spoke on condition of anonymity because he was not authorized to give this information.

This week the rebels lost control of all the territory they once held following an intensified offensive by Congolese troops who are backed by United Nations forces in eastern Congo. After their last major stronghold fell last week, the rebels appeared to flee from the border town of Bunagana to the surrounding hills and forests. Earlier this week the rebels’ civilian leader, Bertrand Bisimwa, announced the rebellion was over, saying he wanted to work with Congo’s government toward finding a political solution to violence in eastern Congo.

Makenga, the M23 commander, is the subject of U.N. sanctions, and it remained unclear what Ugandan officials would do with him.

Under the banner of a regional bloc, Uganda has been hosting peace talks between the rebels and Congo’s government. Those talks have repeatedly stalled, but there were signs a final accord might be signed soon after Congolese troops gained an upper hand against the rebels in recent fighting in eastern Congo.

M23 launched its rebellion in April 2012, becoming the latest reincarnation of a Tutsi rebel group dissatisfied with the Congolese government. A report by U.N. experts has said neighboring Rwanda, whose president is also an ethnic Tutsi, provided weapons, recruits and training to M23 rebels. Rwanda’s government denies the allegations, saying Congo’s government has failed to police its territory.

M23 had been substantially weakened in the past year by internal divisions and waning Rwandan support, according to the U.N. Defections from the M23 went up, totaling 80 in October.

The Congolese military capitalized on these rebel setbacks by pushing ahead with new offensives beginning in August that were supported by a brigade of U.N. forces with a mandate to attack the rebels.