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.

US Secretary of State Marco Rubio pressed Rwanda for an immediate ceasefire in the Democratic Republic of Congo as he voiced alarm over Kigali-backed rebels entering the key city of Goma.

There was gunfire Tuesday in the eastern Democratic Republic of Congo city of Goma, as the United Nations warned of a worrying humanitarian situation amid clashes between Congolese soldiers and Rwandan-backed rebels who attacked the area and claimed to be in control.

The call came as the US urged the UN Security Council to consider measures to halt an offensive by Rwandan troops

The United States, France and Britain pressured Rwanda on Sunday over its support for rebels rapidly closing in on eastern Congo's largest city, as government forces struggled to halt an offensive that has forced thousands of civilians to flee.

Rwanda-backed rebels claim they have captured eastern Congo’s largest city, Goma, as the United Nations describe a “mass panic” among its 2 million people and Congo’s government say the rebel advance was a “declaration of war.

Rwanda-backed M23 rebels have claimed to capture a key city in eastern Democratic Republic of Congo - Goma. This is the latest and sharpest escalation in one of Africa’s longest wars.

Protesters have attacked missions in the capital of the African country as anger grows about the advance of the M23 rebel group.

They spoke out about their assaults in spite the stigma that accompanies survivors of sexual violence and the risk of reprisals from the armed men who attacked them. The Journal article documented how international efforts to curb the use of rape as a weapon of war has fizzled out.

The president of crisis-hit Democratic Republic of Congo was set to meet his Rwandan counterpart at an emergency summit on Wednesday, as fighters backed by Kigali appeared on the brink of seizing the key city of Goma.