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.

M23 is the latest in a long line of Rwandan-backed rebel movements to emerge in Congo's volatile eastern borderlands following two successive wars stemming from Rwanda's 1994 genocide. Rwanda denies supporting the well-trained and heavily armed Tutsi-led group.

Rwandan-backed M23 rebels captured the mining town of Nyabibwe in eastern Congo’s South Kivu province, violating a ceasefire they declared earlier this week, according to NBC News. The rebels now advance toward Bukavu, raising fears of further conflict after seizing the city of Goma last week.