(CNN) -- Congolese soldiers looted villages, reportedly raping women and ransacking homes, late Monday and early Tuesday, U.N. officials said, as the prospect of a sustained ceasefire between government troops and rebel soldiers continued to fade.

The looting came before a nearly hour-long, nighttime gun battle north of the provincial capital of Goma that represented some of the most intense fighting since Rebel leader Gen. Laurent Nkunda declared a unilateral ceasefire on October 29.

Since then, both sides have accused the other of violating the ceasefire in smaller skirmishes that both the U.N. and Democratic Republic of Congo officials say have killed hundreds of people, including civilians.

U.N. spokesman Col. Jean-Paul Dietrich, speaking from Kinshasa, told CNN that Congolese troops began looting the village of Kanyabayonga, about 60 miles (100 km) north of Goma, late Monday.

"They were shooting in the air; they were shooting in houses," Dietrich said. He said U.N. officials received radio reports from local authorities saying the soldiers were also raping women in the village.

He said several hundred soldiers continued looting in villages further north.

Fighting broke out in eastern Congo at the end of August between government forces and rebels led by Nkunda. The fighting is spurred by lingering tensions over the 1994 slaughter of ethnic Tutsis by majority Hutus in neighboring Rwanda. Nkunda says his forces are fighting to defend Congolese Tutsis from Hutu militants who escaped to Congo.

The fighting has worsened an already difficult humanitarian situation. More than 250,000 people have been displaced by the conflict -- adding to roughly 800,000 already driven from their homes by past violence, the U.N. says.

The gun battle late Tuesday was in Kibati, about six miles (10 km) north of Goma.

Dietrich said the cause of the fight was unknown, but was touched off in an area where rebel and government fighters had been camped close to each other.

"We were putting some pressure on them over the last few days that they should withdraw," he said. "There are high tensions -- one small incident can trigger major fighting between the forces."

The U.N. Children's Fund said 29 tons of emergency aid arrived in Goma on Sunday.

"These supplies will contain the spread of cholera and diarrhea, both extremely contagious diseases on the rise in nearly all internally displaced person settlements in North Kivu," said Pierrette Vu Thi, the agency's representative in Congo.

The United Nations also is shipping food, medicine, fresh water and other supplies into camps throughout Congo daily.

There are about 17,000 U.N. troops in Congo. On Tuesday, U.N. Secretary-General Ban Ki-moon called for an immediate ceasefire, saying as many as 100,000 refugees north of Goma have been cut off from relief workers.

Ban said he has requested the U.N. Security Council to authorize an additional 3,000 troops to help control the fighting.

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