(Reuters) -Chaotic scenes unfolded in the eastern Congo city of Bukavu on Saturday after Rwanda-backed M23 rebels reached its outskirts, while a threat by Uganda's army chief to attack a Congolese town raised fears of the conflict flaring into a wider regional war.

The Rwandan-backed rebels' entry into Bukavu follows their capture of Goma, defying international calls for a ceasefire.

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.