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.

A rebel alliance claimed the capture of the biggest city in the Democratic Republic of Congo’s mineral-rich eastern region this week, pushing back against resistance from government troops backed by regional and UN intervention forces.

The weeks-long march of the M23 armed group, which has captured vast swathes of eastern DRC including most of the key city of Goma, has prompted calls for crisis talks and warnings of a looming humanitarian crisis.

M23 rebels captured the key city of Goma in the eastern DRC Monday, forcing thousands of civilians to flee in the latest in a series of advances - Anadolu Ajansı

Democratic Republic of Congo - A million displaced, one story at a time: Protecting women and girls in the heart of conflict

Authorities say the governor of eastern Congo’s North Kivu province has died from injuries sustained in fighting on the front line as M23 rebels close in on Goma.

Rwanda, which diplomats say backs M23 fighters who seized Goma in Democratic Republic of Congo this week, called on Wednesday for a ceasefire across eastern Congo and for Congo to negotiate with the rebels while denying Rwandan troops were involved.

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.

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.

Aid teams from the UN World Health Organization ( WHO) “cannot move freely to support the hospitals, even ambulances cannot run. It’s a situation that in public health is a nightmare,” said Dr Boureima Hama Sambo, WHO Representive in DRC.

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