Rwanda's ally Uganda, unhappy about another rebel group in DR Congo that threatens its security, has also been accused of helping the M23 - with its officers also spotted at Tchanzu. The UN experts say Uganda has also supplied weapons, hosted rebel leaders and allowed cross-border movements of M23 fighters - accusations Kampala denies.

The United Nations says Rwanda-backed rebels captured large parts of eastern Congo’s largest city of Goma including its airport

The United States told Rwanda it was "deeply troubled" by the fall of Goma in eastern Congo to Rwandan-backed M23 rebels, who appeared on Wednesday to have consolidated control over the city of nearly 2 million in just two days.

The militia seized the pivotal city of Goma, threatening a new humanitarian crisis in a region that has suffered decades of fighting.

Rwanda-backed rebels captured large parts of eastern Congo’s largest city including its airport, the United Nations said, as Rwanda’s president joined calls for a ceasefire

The United States urged the United Nations Security Council on Tuesday to consider measures to halt an offensive by Rwandan troops and M23 rebel forces in eastern Democratic Republic of Congo as a conflict there escalates.

Rwanda's President Paul Kagame said he agreed with the U.S. government on the need for a ceasefire in eastern Congo but gave no indication of bowing to calls for Rwandan troops and the M23 rebels they support to withdraw from Goma.

Rwanda-backed rebels have captured large parts of the eastern Democratic Republic of the Congo’s largest city, including its airport, the United Nations said. The move in Goma comes as Rwanda’s President joined calls for a ceasefire in the decades-long conflict.