DRC rebels in streets of Goma Commanders from M23, or the March 23 Movement, had said on Monday that they did not intend to enter Goma, the main city in Congo's east and de facto headquarters for its massive aid effort, unless they were fired upon. But it appears that they disregarded that promise in the early hours of Tuesday. Now there are fears of street-to-street fighting in the city, where most people live in flimsy shelters or tin-shack houses that will be no protection from stray rounds. An M23 rebel stands with his machine gun at a forward position in the hills of Kanyarucinya on the outskirts of Goma, in the east of the Democratic Republic of the Congo (AFP/Getty Images) Aid workers fear they will face massive increases in civilians with war wounds, to add to the humanitarian crisis of more than 50,000 people already fleeing violence earlier this week. There were also reports on Tuesday of fighting to Goma's west, around Mugunga, where most of those tens of thousands of people had sought safety after running from other camps. It will be impossible for the M23, whose total strength is thought to number no more than 2,500 soldiers, to hold Goma, security analysts have said. But there were concerns that Rwanda, which has denied international reports that claim it is funding and arming the M23, could enter the fray in an ostensible bid to "protect" is porous border with Congo. Goma is a effectively contiguous with the Rwandan town of Gisenyi, with the two halves of the population separated only by the poorly-guarded frontier. On Monday, Rwanda and Congo exchanged claims that each other's forces had launched cross-border mortar attacks into each others territory. Rwanda's invasion of Congo, with support from Uganda, prompted a decade of conflict that killed as many as five million people, mostly from hunger and disease.