The M23 militia is ruling over a vast stretch of territory in the eastern part of the Democratic Republic of Congo, threatening the sovereignty of the biggest country in sub-Saharan Africa.

Rwanda-backed rebels battling Congo’s army have pushed into a strategic, mineral-rich town in the east, ignoring calls for a ceasefire this week by the Congolese and Rwandan presidents as the M23 rebel group expands its footprint in the conflict-torn African country.

The leader of a rebel alliance that has seized swathes of east Congo told Reuters on Thursday that insurgents were not bound by a ceasefire call from Congo and Rwanda's presidents and cast any minerals-for-security deal with the U.