Rwanda-backed rebels appeared to be heading toward a third major city in eastern Congo, frightened residents said Tuesday, as international pressure rose over the M23's expansion in the mineral-rich region that's critical for global technology.

The UN human rights chief accused Rwanda-backed rebels who seized a second major city in eastern Democratic Republic of Congo (DRC) of killing children and attacking hospitals and warehouses storing humanitarian aid.

The UN human rights chief has accused Rwanda-backed M23 rebels of committing atrocities, including child executions, after they took control of a second major city in eastern Congo. The ongoing conflict has resulted in significant casualties and displacement,