"I want to remind all parties that when the laws of war are violated, personal criminal responsibility may ensue, particularly for those in positions of command and control," Ban said in a statement issued at U.N. headquarters in New York.

Hostilities between a rebel militia led by General Laurent Nkunda and government forces have escalated in recent weeks in North Kivu. As many as 252,000 Congolese have fled their homes, bringing to about 1 million the total refugees from hostilities that have plagued the African nation.

Ban said he was "somewhat encouraged" by talks between the presidents of the Democratic Republic of the Congo and Rwanda, Joseph Kabila and Paul Kagame, at a summit in Nairobi last weekend, and declarations calling for a cease-fire.

The secretary-general urged the combatants cease hostilities to allow humanitarian aid to reach about 100,000 "increasingly desperate" internally displaced citizens cut off by the fighting in Rutshuru and East Masisi.

"Despite the Nairobi declaration, there are continued reports of sporadic fighting," Ban said.

"First and foremost, we must stabilize the situation on the ground and end this needless violence and suffering. U.N. agencies are delivering food, medicine, fresh water and sanitation supplies to areas where they can operate, most particularly in Goma."