Rwanda-backed militias are besieging a city of millions in DRC. Disaster will follow if the west stands by | Vava Tampa

Kagame's regime is funding rape, killings and torture by the M23 militia, who have now cut off the city of Goma. But he can be stopped

The M23 militia group attacked the town of Sake in North Kivu last month, wounding eight UN peacekeepers and sending much of its population fleeing towards the provincial capital, Goma. The fall of the town in the east of the Democratic Republic of the Congo (DRC) means the M23 now controls all roads in and out of Goma - and, by extension, critical mining sites and trading networks.

If the M23 wanted to overrun the capital, as it did in 2012, it would have done so by now. So why hasn't it? The militia would struggle to keep hold of the city without the support of neighbouring Rwanda. Three UN investigations, the latest in December, have concluded that the M23 is armed and supported by President Paul Kagame's regime. The UN imposed sanctions on the group in February.