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.'

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.