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.

Democratic Republic of Congo's M23 rebels are moving south towards Bukavu, the capital of South Kivu province, in what appears to be an attempt to expand their area of control in the country's east after capturing the city of Goma.

The Rwandan-backed M23 group on Friday advanced south after seizing the biggest city in mineral-rich eastern DR Congo, in violence that according to the UN has killed at least 700 people in less than a week.