Rwanda-backed rebels in eastern Congo have claimed that they have seized a second airport in the region following a days-long advance towards the Kavumu airport.

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.

Rwanda-backed rebels in eastern Congo on Friday entered the region's second-largest city of Bukavu, local and civil society leaders said, the latest ground gained since a major escalation of their yearslong fighting with government forces.