A rebel group has said it has advanced into Bukavu, the second largest city in the eastern Democratic Republic of Congo (DRC), with residents reporting looting and fighters in the streets.

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

(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.

M23 fighters and Rwandan troops entered the DR Congo provincial capital of Bukavu on Friday, security and humanitarian sources said.

The M23 captured Goma, a city of nearly two million people, last week after a lightning advance in DR Congo's eastern region. At least 700 people in the city were killed and close to 3,000 injured as the rebels clashed with DR Congo's army and its allies, according to the UN and the Congolese government.

(Reuters) -Rwandan-backed M23 rebels appeared on Friday to be closing in on eastern Democratic Republic of Congo's second-largest city, Bukavu, as they seized control of the nearby airport of Kavumu,

M23 rebels, backed by Rwanda, continue their advance in South Kivu province after capturing Goma. Local sources report that the group has seized a strategic airport. Meanwhile, the UN continues to raise alarms over the deteriorating humanitarian situation in eastern Congo.