Congolese security forces on Tuesday tried to slow the advance of Rwanda-backed M23 rebels who say they have captured Goma after entering eastern Congo's largest city, as U.N. officials reported violence,

Rebels seized the airport of east Congo's largest city, Goma, on Tuesday, potentially cutting off the main route for aid to reach hundreds of thousands of displaced people, after capturing the city in an offensive that left dead bodies lying in the streets.

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.