Rebel fighters have not honoured a pledge to pull out of the town of Bukavu in the Democratic Republic of Congo, UN officials say.
Gen Nkunda's men entered Bukavu on Wednesday
They were meant to have withdrawn by Friday evening, but a UN spokesman said renegade fighters remained in the area.
The rebel commander earlier said his men had started leaving the town.
Rebels overran UN-held Bukavu on Wednesday, sparking violent anti-UN protests in DR Congo's capital Kinshasa amid fears for a fragile peace process.
The spokesman for UN peacekeepers, Sebastian Lapierre, told the BBC's Robert Walker in Bukavu that the commander of the dissident soldiers had not yet respected a commitment to withdraw his forces.
Mr Lapierre said that although some troop movements had been reported, there were still soldiers in Bukavu.
The UN is concerned over reports that the rebels continue to loot property and intimidate and abuse locals, and says it has stepped up its patrols.
According to the deal struck by the UN on Thursday, the rebels were meant to have withdrawn from Bukavu to bases and outposts around the town.
But, reports our correspondent, there was some confusion as to how far they would pull back, with the UN expecting a full withdrawal from the city but the rebels' leader, Brig Gen Laurent Nkunda, insisting they would only evacuate the city centre.
Local UN commander Gen Jan Isberg had said he expected all the renegade forces to leave Bukavu by the end of Friday.
He said force would be used to disarm them, if they returned with their weapons.
However, peacekeepers were unable to enforce a similar deal struck last week.
Meanwhile, hundreds of people have again protested in the capital Kinshasa against the UN peacekeepers' failure to stop the capture of Bukavu.
Five people died in Kinshasa on Thursday, when UN troops fired into a crowd trying to loot the UN office.
Police fired live bullets to disperse a crowd trying to reach the UN base.
The protesters burnt tyres and smashed cars windows.
Elsewhere, the streets of Kinshasa are empty following Thursday's violence and several international flights have been cancelled.
President Joseph Kabila has said he understands the rioters' anger but said this did not justify their "excesses".
The fighting in Bukavu has sparked fears that DR Congo's fragile peace process may be unravelling.
Rebel leader Gen Nkunda says: "I'm not a mutineer because I'm not fighting the government. I just came to kick out troops... who were killing a section of the Congolese community."
Traders and residents returned to the streets of Bukavu on Friday, the AP news agency reports.
Renegade commanders - who are ethnic Banyamulenge, related to Rwandan Tutsis - say government forces have been attacking members of their community.
The dissident soldiers are from a former Rwandan-backed rebel group, the RCD, that was supposed to join the national army.
Gen Nkunda has several thousand men under his control. They are reinforcing Col Jules Mutebusi, whose militia first clashed with the army last week.
Additional UN peacekeepers were sent to Bukavu last week, following fighting between the dissidents and regular troops.
But a UN spokesman said they did not a mandate to use force to stop the rebel advance.
But President Kabila has accused neighbouring Rwanda of being behind the rebels.
Bukavu is "under the control of Rwandan occupants", he said, telling the BBC it was "a situation of war".
Rwanda has denied any involvement.
The UN said Rwandan troops had been spotted in DR Congo north of Bukavu six weeks ago, although they were all supposed to have left as part of last year's peace deal.
Is this the end of peace in DR Congo? Should the UN have stopped the rebel advance?
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