Democratic Republic of Congo President Felix Tshisekedi has vowed “a vigorous and coordinated response” against a rebel alliance that has besieged swaths of the nation’s mineral-rich east and forced hundreds of local troops and foreign mercenaries to surrender.

The weeks-long march of the M23 armed group has prompted calls for crisis talks, as well as rising international criticism and warnings of a looming humanitarian crisis.

The weeks-long march of the M23 armed group, which has captured vast swathes of eastern DRC including most of the key city of Goma, has prompted calls for crisis talks and warnings of a looming humanitarian crisis.