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.

Congolese President Félix Tshisekedi has vowed to restore government authority in the east, where Rwanda-backed M23 rebels have seized control of the city of Goma and are reportedly advancing south to take more territory.

Unconfirmed reports say the Rwanda-backed rebels are currently advancing towards Bukavu, the second-biggest city in the mineral-rich east, despite international calls for a ceasefire. In a televised address after the fall of Goma,

President of the Democratic Republic of Congo said on Thursday that his troopers are fighting an insurgence by the Rwandan-backed militant group M23 which recently captured swaths of land in the east.

Democratic Republic of Congo President Felix Tshisekedi, speaking publicly for the first time since Rwandan-backed rebels seized the eastern city of Goma, said his government was preparing a response and warned of “unpredictable consequences” for the region.