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.

Rwanda-backed rebels captured a second major strategic city in the Democratic Republic of Congo, expanding their dominance over the country’s mineral-rich east amid the widening conflict.

M23 rebels backed by Rwanda took the city of Goma in a bloody battle. This weekend, the group entered the gold-trading center of Bukavu in eastern Congo after government soldiers fled.