The United Nations Security Council, Secretary-General Antonio Guterres and senior U.N. officials are calling for the M23 to immediately cease hostilities and withdraw from occupied territories. They have called for the withdrawal of Rwandan forces and a return to the Luanda process of mediation overseen by Angolan President Joao Lourenco.

"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.

Thousands fled the city of Goma on Monday as fighting raged between Congolese forces and rebels backed by neighboring Rwanda, who claimed to have captured eastern Congo’s largest regional hub.