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.

M23 rebels claim they now control the Congolese city of Goma—an act Congo's government described as a 'declaration of war.'

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.

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.

GOMA, Democratic Republic of Congo (Reuters) -Congolese rebels said on Sunday they had taken Goma, the biggest city in the east of the mineral-rich country, after a lightning advance that has forced thousands of people to flee and fuelled concerns of a regional war.

Mount Goma

STORY: Rwandan-backed rebels marched into eastern Democratic Republic of Congo's largest city on Monday, according to witnesses.That's prompted thousands of people, including Congolese soldiers, to flee across the border into Rwanda.

Congo has severed diplomatic ties with Rwanda as fighting between Rwanda-backed rebels and government forces rages around the key eastern city of Goma.

GOMA, Congo (AP) — 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.

Congolese rebels and allied Rwandan troops claimed on Monday to have captured the mineral-rich city of Goma, as thousands fled fighting that killed at least 13 peacekeepers over the weekend...

Thousands of prisoners in the eastern Democratic Republic Congo (DRC) city of Goma escaped in a mass jail break on Monday as Rwanda-backed rebels said they had captured the strategic city.