Congolese army soldiers desecrate the body of an alleged M23 fighter in Kanyarucinya. (AFP)
Monusco spokesperson Felix Basse said UN troops were monitoring the situation in the area of the resource-rich east of the country controlled by the rebels during the current lull in fighting.
"At the moment, it is time to consolidate the positions recovered by the army pending further actions in the future," said Basse.
"The M23, which in practice controls the territory of Rutshuru [north of Goma]", has "imposed a curfew on civilians", said the Senegalese officer.
He said this was "completely unacceptable" and that the situation was "being monitored by UN troops until future action".
UN special envoy Mary Robinson said on Wednesday she believed discussions between Kinshasa and the rebels could yet succeed in bringing an end to attacks on civilians in the region.
The negotiations, which opened in December in Kampala and have been suspended since May, were not "at an impasse," said Robinson during a press conference in the Congolese capital.
The former Irish president told the audience she believed a solution would be found, but admitted she was "a bit frustrated" with the progress so far.
Rebel retreat
The rebels, who seized Goma for 12 days in November before withdrawing to the surrounding hills under international pressure, retreated this week to around 30km north of the city in the face of a new UN-backed offensive by the army.
The M23 was launched by Tutsi soldiers who mutinied from the army in April 2012 and turned their guns on their former comrades.
The UN and the Kinshasa government accuse neighbouring Rwanda of supporting the rebels, a charge Kigali denies.
The latest comments came as defence chiefs and foreign ministers from Africa's Great Lakes region met in Uganda in the latest bid to end the fighting in DRC.
Congolese troops, backed by a special United Nations force, launched a fresh assault against the M23 army mutineers in the turbulent North-Kivu province late last month On Friday, the rebels retreated to Kibumba, some 30km north of Goma, the capital of the mineral-rich province of North Kivu.
Although there has been no fighting since Sunday, a high-ranking army officer said on Monday that an offensive on Kibumba was planned "in the near future".
He added that army positions were within twokm of the town.
Army spokesperson Olivier Hamuli said the goal was to "consolidate" positions it had gained in the east, "knowing that Rwanda is behind" the M23.– AFP