Rwanda-backed M23 rebels faced pockets of resistance from army and pro-government militia overnight after entering eastern Congo's largest city Goma in the worst escalation of a conflict that has run for more than a decade.

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.

M23 rebels, reportedly backed by Rwanda, claimed control of Goma, the largest city in eastern Congo, early Monday. This development comes as the Congolese government cut diplomatic ties with Rwanda, with Congolese spokesman Patrick Muyaya calling the situation a "declaration of war.

Rwanda-backed rebels have claimed they captured eastern Congo’s strategic city of Goma, the hub of a region containing trillions of dollars in mineral wealth that remains largely untapped. Analysts said the M23 fighters aimed to control the city of about 2 million people and perhaps other areas in the region nearly 1,

A rebel alliance spearheaded by the ethnic Tutsi-led M23 militia said it had seized the lakeside city of more than 2 million people.

M23 rebels in the Democratic Republic of Congo were reported to have taken the key eastern city of Goma in fierce fighting with government forces that sent streams of refugees fleeing area communities.

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