(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.

Analysts say the deadly march by Rwanda-backed rebels across eastern Congo could widen into a regional conflict drawing in even more countries, and two neighboring nations with the most involvement in the mineral-rich area might be the key to stopping the violence.