There was gunfire Tuesday in the eastern Democratic Republic of Congo city of Goma, as the United Nations warned of a worrying humanitarian situation amid clashes between Congolese soldiers and Rwandan-backed rebels who attacked the area and claimed to be in control.

"Active zones of combat have spread to all quarters of the city, all the neighborhoods of the city," Lemarquis, the deputy U.N. envoy and top U.N. aid official in the DRC, told reporters in New York via video from Kinshasa.

There are growing international calls for peace talks to end the escalation of violence in the east of the Democratic Republic of Congo. The fate of the economic and trading hub Goma is still unclear. UN officials have said the situation is chaotic with fighting continuing in parts of the city.