Katanty and Sonia Rolley GOMA, Democratic Republic of Congo (Reuters) -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,

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

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.

Fighting between M23 and Democratic Republic of the Congo forces has displaced 400,000 since the start of this year, according to the United Nations

Mount Goma

Congo has severed diplomatic ties with Rwanda as fighting between Rwanda-backed rebels and government forces rages around the key eastern city of Goma, leaving at least 13 peacekeepers and foreign soldiers dead and displacing thousands of civilians.

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.

In the aftermath of its withdrawal from Goma, the M23 suffered a series of heavy defeats at the hands of the Congolese army, which was backed by a multinational force. The M23 were subsequently expelled from the country. M23 fighters then agreed to be re-integrated into the army in return for promises that Tutsis would be protected.

Social media footage shows armed men in Congo's Goma walking on grounds of airport amid sounds of fierce fighting.

Rwandan-backed rebels have marched into east Democratic Republic of Congo's largest city Goma and DR 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.

PRETORIA - Rwandan President Paul Kagame will meet his DRC counterpart face-to-face within 48 hours.