Fighting across the largest city in eastern Democratic Republic of Congo and "is still very much ongoing ... it's not over yet," senior U.N. official in Congo, Bruno Lemarquis, said on Monday after Rwandan-backed M23 rebels claimed to have control of Goma.

M23 militia fighters, alongside Rwandan troops, are pushing into the eastern DR Congo city of Goma, capital of the mineral-rich North Kivu province.

Rebels seized the airport of east Congo's largest city, Goma, on Tuesday, potentially cutting off the main route for aid to reach hundreds of thousands of displaced people, after capturing the city in an offensive that left dead bodies lying in the streets.