The UN top diplomat Ban Ki-moon yesterday called for urgent measures to contain the crisis in the eastern Democratic Republic of Congo (DRC), where clashes between rebels and government forces have displaced tens of thousands of people over the past weeks.

Speaking at a United Nations-backed regional summit of African leaders in Nairobi, Ban stressed that neither the vast African nation nor the surrounding region can risk a return to conflict.

"I must begin by saying that I have come to Nairobi with a heavy heart. We meet today as, once again, the interlinked tensions and conflicts in the Great Lakes region threaten hard won progress," he said.

"When the world has been struggling to address the impending global challenges of Climate Change, the Millennium Development Goals, the food crisis, and more recently, the global financial crisis, there is no time to lose," Ban said.

Fighting in the province of North Kivu between government forces (FARDC) and the National Congress in Defense of the People (known as the CNDP), a militia led by former general Laurent Nkunda, has displaced as many as 253,000 Congolese in recent months.

The Nairobi summit, hosted by the African Union (AU), brought together DRC President Joseph Kabila and President Paul Kagame of Rwanda, which borders North Kivu, as well as the leaders of Kenya, Uganda, Tanzania, Burundi and South Africa.

"Before anything else, we must take urgent measures to contain the present crisis created by the upsurge of fighting in eastern DRC," Ban told the leaders.

"Neither the DRC, nor Rwanda, nor the rest of the central Africa region can afford to be dragged back into conflict. The international community cannot allow this to occur."

The UN top diplomat voiced deep concern at fresh fighting in North Kivu and urged all armed groups to get behind efforts to broker a political solution to the current crisis.

He stressed the need to deal with the "armed group challenge," pointing out that the grave consequences of foreign armed groups in the DRC are felt not only by the Congolese people, but they also continue to weigh heavily across region.

"For far too long, peace and security in your region has been threatened by armed groups, domestic and foreign, present on the soil of the Democratic Republic of the Congo. They have been operating from there with impunity, aggravating strains between your countries and between your peoples."

In a move aimed at seeking a political solution to the crisis, Ban said that "our urgent task is to turn the Nairobi and Goma principles into concrete steps on the ground," referring to previous agreements which provided for a ceasefire, the disengagement of troops and the disarmament of armed groups.

"We need to end the conflict in the east, and prevent it from spilling over into the wider sub-region. We need to restore the authority of the State, and consolidate the stability that has been achieved in the rest of the country," he added.

"As leaders of Africa, you have a historic responsibility - this is a critical moment for the Great Lakes region, and for Africa as a whole. We must put the cycle of violence behind us. We must build a shared future of stability, peace, development and human rights for all citizens of your countries," Ban stated.

The UN chief called for the strengthening of the Congolese national army and the existing UN peacekeeping force. "The capacity of the Congolese national army must be strengthened considerably if it is to do its proper job. We have asked the Security Council for the reinforcement of MONUC."

The UN mission in DRC (MONUC) is the 17,000-strong peacekeeping force, the largest such force in the world now. He said that only political agreement can ultimately end the escalating violence in the war-torn West African country.

"It is only at political level, here in your region, that lasting solutions can be found.. there can be no military solution to this crisis."

Ban also told regional leaders to urge General Laurent Nkunda to stop his military offensives and pull back to positions he held in January 2008, when an agreement was signed with the rebel leader. "This must also apply to other armed groups as well."

Rwanda has been accused of supporting eastern Congo rebels led by General Nkunda, whose 8,000-strong militia is fighting the government based in Kinshasa.

The troops have threatened to overrun the city of Goma. Also, Uganda's Lord's Resistance Army (LRA) has also contributed to instability in other parts of DRC.