Rwandan-backed M23 rebels appeared on Friday to be closing in on eastern Democratic Republic of Congo's second-largest city, Bukavu, as they seized control of the nearby airport of Kavumu, prompting Congolese troops to withdraw in some areas.

The Rwandan-backed rebels' entry into Bukavu follows their capture of Goma, defying international calls for a ceasefire.

Earlier on Friday, the Congolese army confirmed that M23 fighters had taken control of Kavumu airport, north of Bukavu, and that Congolese troops had pulled back with their equipment. The rebels have been trying to push south towards Bukavu since they seized Goma, the largest city in eastern Congo, at the end of last month.