(Reuters) -Chaotic scenes unfolded in the eastern Congo city of Bukavu on Saturday after M23 rebels reached its outskirts, while Congo's prime minister declined to comment on a threat by Uganda's army chief that raised fears of a spiral into a wider regional war.

Residents and business owners in eastern Congo’s second largest city are sitting in wait after a night of loud gunfire marking the ongoing advance of Rwanda-backed rebels.

Chaotic scenes have been unfolding in Bukavu in eastern Democratic Republic of Congo as the M23 rebel group continues its offensive in the region. On Saturday there were reports of sporadic gunfire and widespread looting in the city, including at a World Food Programme depot, with residents sheltering in their homes.