Rwanda-backed rebels who captured eastern Democratic Republic of Congo’s largest city said on Thursday they want to take their fight to the far-off capital, Kinshasa, while Congo’s president called for a massive military mobilisation to resist the rebellion and his defence minister rejected calls for talks.

Rwanda-backed rebels were expanding their presence in eastern Congo after capturing Goma, the region's major city, the U.N. said Friday, also expressing concerns over executions it learned were carried out by the rebels in recent days following a major escalation of their yearslong rebellion.

The Rwandan-backed armed group M23 moved south as it closed in on a key military airport in DR Congo on Friday, a day after pledging to take the capital Kinshasa and as international criticism mounted.