(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.

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.

M23 now controls nearly all of North Kivu and the province’s vast mineral wealth—including tin (cassiterite), tantalum (coltan), tungsten (wolframite), and gold, which are critical for global electronics and industrial production.