The United Nations has called on the rebels to lay down their arms and withdraw immediately from Goma.

The United Nations High Commissioner for Refugees said Tuesday that aid groups had been able to resume deliveries to sites around Goma over the weekend, after fighting caused days of disruption. The U.N. refugee agency said it was trying to reach 110,000 people with supplies of food, soap and water containers.

Many of those who have fled to refugee camps around Goma are in urgent need of shelter and clean water, the UNHCR said.

"Sanitary conditions remain a major challenge due to the lack of toilets and water supply points," it said. Cases of vomiting, diarrhea and respiratory infections have already been recorded, it said, with the last due to people having to sleep outside without shelter from the rain.

The Democratic Republic of the Congo has seen far more than its share of violence over the decades. Civil wars -- most recently in the 1990s through 2003 -- have left millions dead across the country and displaced entire generations.