U.S. Secretary of State Marco Rubio called for a urgent cease-fire in the conflict in eastern Democratic Republic of Congo saying Washington was "deeply troubled" by a recent escalation in the fighting.

Democratic Republic of Congo's M23 rebels are moving south towards Bukavu, the capital of South Kivu province, in what appears to be an attempt to expand their area of control in the country's east after capturing the city of Goma.

By Yassin Kombi and David Lewis GOMA, Democratic Republic of Congo (Reuters) -As an East African bloc urged an immediate ceasefire in eastern Democratic Republic of Congo, Rwandan-backed M23 rebels who seized the city of Goma extended their advance on Wednesday,

Residents of the besieged city of Goma, in the east of the Democratic Republic of Congo, say they are gripped by fear as gunshots continue to ring out around their homes, days after rebel forces claimed they had taken over.

Pope Francis expressed his “extreme concern” for the worsening security situation in the Democratic Republic of Congo.

Many blame the United States, France and other allies for allowing neighboring Rwanda to fuel a conflict in the country’s east.

Rioters stormed embassies and started fires in Democratic Republic of Congo's capital Kinshasa, drawing tear gas from police, in an eruption of protests over a Rwandan-backed rebel offensive in the east.

A conflict that has raged for decades reached a flashpoint this week when rebels backed by Rwanda marched on a key Congolese city in a bid to occupy territory and exploit minerals.