United Nations Secretary-General Ban Ki Moon has visited the eastern Democratic Republic of Congo following a recent surge in fighting there between government and rebel forces.
A truce was announced for the duration of his visit.
At least 20 people have been killed since Monday in fighting between government and M23 forces, who rebelled in May last year.
The rebels are believed to have some support from Rwanda and Uganda.
A BBC correspondent says that by some estimates there could be as many as 50,000 armed men in the region, belonging to several dozen armed groups.
On Wednesday, the World Bank announced an aid package worth $US1 billion to help DR Congo and its neighbours.
World Bank head Jim Yong Kim said the money would be used for health, education, cross-border trade and hydroelectricity projects.