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.

Rwandan-backed rebels marched into east Congo's largest city Goma on Monday and Congolese troops exchanged fire with the Rwandan military across the border, in the worst escalation of a long-running conflict for more than a decade.

Residents in eastern Congo's largest city, Goma, woke up on Monday morning uncertain about who is in control of the city, which Rwanda-backed rebels claimed to have captured.

The M23 militia, funded and directed by Rwanda, said it had seized the city of Goma, terrifying its people, many of whom sought shelter there after fleeing the rebel advance.

A U.N. official says Congolese rebels and allied Rwandan forces have entered the outskirts of Goma and the airport in the key eastern city is no longer in use.

THE Democratic Republic of Congo has severed diplomatic ties with Rwanda as fighting intensifies between Rwanda-backed M23 insurgents and Congolese government forces in Goma. The war has left at least 13 United Nations peacekeepers and foreign soldiers dead and displaced thousands of civilians.

Residents of eastern Congo's largest city of Goma greeted the arrival of Rwanda-backed rebels with trepidation on Monday, some staying indoors and others coming out to cheer in what one called a "show" of happiness.

Thousands fled the city of Goma on Monday as fighting raged between Congolese forces and rebels backed by neighboring Rwanda, who claimed to have captured eastern Congo’s largest regional hub. Pockets of chaos and gunfire had some people hunkering down as the rebels marched into the city with a population of about 2 million.

Troops from Democratic Republic of Congo and Rwanda have been firing at each other across their shared border in the eastern Congolese city of Goma, where Rwandan-backed rebels launched an offensive,