The Security Council and UN chief Ban Ki-moon have expressed concern about recent heavy fighting in the Democratic Republic of Congo's Nord Kivu province between government troops and forces loyal to renegade general Laurent Nkunda.

The 15-member council heard an impromptu briefing by UN Assistant Secretary General Edmond Mulet on the latest developments in Nord Kivu.

Afterward, Italy's UN envoy Marcello Spatafora, who chairs the council this month, said members "expressed serious concern at the humanitarian consequences of the recent fighting" there.

He added that the members stressed "the obligation of all parties under internatiomal humanitarian law and the primary responsibility of the government regarding the protection of civilians."

Ban, who is attending a climate change conference in Indonesia, is "deeply concerned about the intense fighting in Nord Kivu in recent days," and was "particularly troubled by reports of massive displacement and mistreatment of the population," according to his press office.

The UN chief urged Nkunda loyalists to lay down their arms and noted that the UN mission in DRC (MONUC) backed Kinshasa's "efforts to establish legitimate state authority in the eastern DRC, and to meet its commitments under the Nairobi Communique," according to a statement.

Under the Nairobi deal reached by DRC and Rwanda last month, Kigali committed to seal its borders with its neighbor to prevent the movement of any armed groups, in particular Nkunda's, and to curtail any support they might access.

The presence of the rebels -- most notably the Rwandan Hutu militia known as the Democratic Forces for the Liberation of Rwanda (FDLR), whom Kigali accuses Kinshasa of backing -- has long strained ties between the two neighbors.

Spatafora said council members expressed support for Kinshasa's "legitimate effort to assert sovereignty over all of its territory" and recalled the council's demand that "all illegal armed groups in eastern DRC lay down their arms, in particular the forces of laurent Nkunda and the FDLR."

Kigali accuses some of the rebels -- estimated to number 6,000 -- of taking part in the 1994 Rwandan genocide, which the United Nations says resulted in some 800,000 mostly Tutsi dead.

Rwanda in turn denies accusations that it is supporting Nkunda -- an ethnic Tutsi who claims he is protecting DRC's Tutsi population -- against government troops in the eastern DRC.