Rwandan-backed M23 rebels have seized control of a mining town in eastern Democratic Republic of Congo's South Kivu province, eight sources said on Wednesday, in an apparent violation of a unilateral ceasefire they declared this week.

Goma remains “under occupation” by Congo’s M23 rebels and the ceasefire they announced has been broken as their forces engage in heavy fighting along the main route to South Kivu’s main city Bukavu.

Rwandan-backed rebels are gaining ground in eastern Congo despite the unilateral ceasefire they declared earlier this week

The rebels said the ceasefire would start Tuesday. The announcement came shortly after the U.N. said 900 people were killed in last week’s fighting in Goma between rebels and Congolese forces.