By Yassin Kombi and Sonia Rolley GOMA, Democratic Republic of Congo (Reuters) -Rebels seized the airport of east Congo's largest city Goma on Tuesday, potentially cutting off the main route for aid to reach hundreds of thousands of displaced people,

After 3 UN peacekeepers were killed in eastern Congo, Guterres emphasised that attacks against UN staff may constitute a war crime United Nations chief Antonio Guterres called on Sunday on Rwandan forces to withdraw from Democratic Republic of Congo (DRC) and halt support for fighters advancing on the key Congolese city of Goma.

M23 rebels, reportedly backed by Rwanda, claimed control of Goma, the largest city in eastern Congo, early Monday. This development comes as the Congolese government cut diplomatic ties with Rwanda, with Congolese spokesman Patrick Muyaya calling the situation a "declaration of war.

GOMA, Democratic Republic of Congo (Reuters) -Rwandan-backed rebels marched into east Congo's largest city Goma on Monday and troops from the east African neighbours exchanged fire over the border in the worst escalation of the long-running conflict for more than a decade.

M23 rebels in the Democratic Republic of Congo were reported to have taken the key eastern city of Goma in fierce fighting with government forces that sent streams of refugees fleeing area communities.

M23 rebels said they have advanced into Goma, a large city in the eastern Democratic Republic of Congo. Hundreds of thousands of residents have been displaced.

The UN chief Antonio Guterres said Rwanda was backing M23 rebels as they advance towards the city of Goma in the Democratic Republic of Congo. DW has more.

Gunshots rang out Sunday night in the centre of the besieged Congolese city of Goma, AFP journalists heard, after the Democratic Republic of Congo accused Rwanda of sending fresh troops across the border to capture the strategic hub.

United Nations chief Antonio Guterres on Sunday urged Rwanda to withdraw its forces from the eastern Democratic Republic of Congo where fierce fighting raged as Kigali-backed fighters closed in on the major city of Goma.

Congolese rebels and allied Rwandan forces entered the outskirts of Goma on Sunday and the airport in the key eastern city was no longer in use, the top U.N. official in the country said. Thousands fled the fighting that also killed at least 13 peacekeepers.

United Nations chief Antonio Guterres, meanwhile, called on Sunday on Rwandan forces to withdraw from Congo and halt support for fighters advancing on the key Congolese city of Goma.

The United Nations is deeply concerned by the M23 rebel group advancing towards South Kivu province in the Democratic Republic of the Congo DRC a U