GOMA, Congo -- Rebels seized the strategic provincial capital of Goma Tuesday, raising the specter of a regional war.

The M23 rebel group, created just seven months ago, took the city of more than 1 million people in eastern Congo, and its international airport on Tuesday, officials and witnesses said.

Explosions and machine-gun fire rocked the lakeside city as the M23 rebels pushed forward on two fronts: toward the city center and along the road that leads to Bukavu, another provincial capital to the south. Civilians ran down sidewalks looking for cover, and children shouted in alarm.

Thousands of Goma residents fled across the border to Rwanda, according to residents of the lakeside city of Gisenyi.

By early afternoon the gunfire had stopped and M23 soldiers marched down the potholed main boulevards, unimpeded. Their senior commanders, whom the United Nations has accused of grave crimes including recruiting child soldiers, summary executions and rape, paraded around the town in all-terrain vehicles, waving to the thousands of people who left their barricaded houses to see them.

advertisement | advertise on newsday

The United Nations peacekeepers, known by their acronym MONUSCO, were not helping the government forces during Tuesday's battle because they do not have a mandate to engage the rebels, said Congolese military spokesman Olivier Hamuli, who expressed frustration over the lack of action by the peacekeepers.

A UN spokesman said in New York that the nearly 1,500 UN peacekeepers in Goma held their fire to avoid triggering a battle.

The peacekeepers "cannot substitute for the efforts of national forces" in Congo, said spokesman Eduardo del Buey. "Do you open fire and put civilians at risk, or do you hold your fire, continue your patrols, observe what's happening and remind the M23 that they are subject to international humanitarian and human rights law?"

The rebels are believed to be backed by neighboring Rwanda.