Democratic Republic of Congo troops have returned to the eastern city of Goma, although rebels who occupied the city for nearly two weeks remain close by.
Rebels are threatening to retake the town if Congo's government goes back on a promise to hold negotiations with them.
M23 rebels were to withdraw 20 kilometers from the North Kivu provincial capital. But residents and officials say some of the rebels remain on the outskirts of town, only three kilometers away.
Despite the slow retreat, the rebel movement allowed about 600 army troops to enter Goma Monday, along with some government officials.
In another development Monday, U.N. experts made new allegations that Rwandan solders took part in the rebels' capture of Goma last month. In a report leaked to the media, the experts told the U.N. Security Council that Rwanda provided major backing to the rebels, including troops.
U.N. experts have also previously accused Uganda of supporting the M23 rebels. Both Uganda and Rwanda deny the allegations.
M23 is made up of former rebels who were integrated into the Congolese army before deserting earlier this year, complaining of discrimination and poor treatment.
Since launching an insurgency in April, the rebels have won battles against Congolese troops and seized land in North Kivu province. On Wednesday and Thursday, the group looted homes as it pulled out of the town of Sake.
Congo's government has tried for years with little success to pacify the east, where rebel and militia groups compete for control of the region's mineral wealth.