It was one of the deadliest battles in decades in the Democratic Republic of Congo.

After the city of Goma fell to a rebel group known as M23 last week, the International Red Cross said that civilians had paid a heavy price, and that the death toll was expected to go up as more bodies were found.

With the rebels said to be getting backing from another Central African county, Rwanda — the Rwandans deny this — there was fear that the conflict could grow into a broader war among the neighboring countries and their allies.

Millions have died in the past 30 years in Congo amid ethnic tensions and disputes over access to land and mineral resources. But rarely have so many been killed within just a few days, experts told Elian Peltier, a New York Times correspondent who traveled to Goma.