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.

A major offensive by Rwandan-backed M23 rebels in east Democratic Republic of Congo appeared to have stalled on Saturday after the army took back some ground, two civil society sources and a local official said.

Authorities confirmed 773 bodies and 2,880 injured persons in Goma's morgues and hospitals, Congolese government spokesperson Patrick Muyaya told a briefing in the capital, Kinshasa, adding that the death toll could be higher.