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 gained ground in eastern Congo on Wednesday despite the unilateral ceasefire they declared earlier this week, taking control of a city 60 miles (96 kilometers) from the provincial capital of Bukavu,

Rwanda, which diplomats say backs M23 fighters who seized Goma in Democratic Republic of Congo this week, called on Wednesday for a ceasefire across eastern Congo and for Congo to negotiate with the rebels while denying Rwandan troops were involved.

Congolese troops have fought back against Rwanda-backed rebels who the U.N. says are moving fast into the South Kivu province after seizing the region’s largest city and an international airport

Rwanda-backed M23 rebels last week captured regional capital Goma in an anarchic and mineral-rich part of Democratic Republic of Congo.