Increasing violent unrest in eastern DR Congo may spark a huge increase in the numbers of people fleeing the fighting, the United Nations has warned.
More than 160,000 people have already been displaced this year in the region's North Kivu province.
Aid agencies believe a further 280,000 people may flee in the next six months.
The instability, which involves dissident Congolese troops and Rwandan rebels, has seen villages attacked by armed groups which loot, rape and kill.
Humanitarian workers in North Kivu say fresh waves of internally displaced people are arriving at camps on a daily basis.
Patrick Lavand-Homme, the head of the UN's humanitarian office in northern Kivu, said: "What we fear in the coming months is that if more military operations are taking place, we might increase the number of displacement.
"We've forecast an extra 280,000 displaced persons for the next six months."
Troops loyal to the dissident Congolese General Laurent Nkunda are known to operate in North Kivu.
An ethnic Tutsi, Gen Nkunda claims he is defending his people from Rwandan Hutu rebels, suspected to have participated in Rwanda´s 1994 genocide, who have been in eastern DR Congo ever since.
BBC Africa editor Martin Plaut says Gen Nkunda has been supported by neighbouring Rwanda.
The Rwandans are determined to prevent those Hutus who fled into DR Congo after the genocide from rebuilding their strength on foreign soil, he says.
Earlier this year, negotiations between the Kinshasa government and General Nkunda led to some of his men being integrated into the national army.
But instead of diffusing Nkunda's influence, it appears to have given him control of these "mixed brigades".
Moreover, the BBC Africa editor says that the government's vacillating position has left UN peacekeepers unwilling to confront the general's forces.
It is thought that troops loyal to Gen Nkunda are responsible for much of the insecurity.
Earlier this week a patrol by UN peacekeepers discovered at least six bodies at two locations in the province where members of one of the mixed brigades had recently been camping.