Rwanda-backed rebels were expanding their presence in eastern Congo after capturing Goma, the region's major city, the U.N. said Friday, also expressing concerns over executions it learned were carried out by the rebels in recent days following a major escalation of their yearslong rebellion.

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-backed rebels who captured eastern Congo's largest city said Thursday they want to take their fight to the far-off capital, Kinshasa, while Congo’s president called for a massive military mobilization to resist the rebellion and his defense minister rejected calls for talks.

Rwanda-backed M23 rebels are moving “rapidly” through South Kivu province toward the city of Bukavu in eastern Democratic Republic of Congo, the United Nations said.

M23 rebels on patrol in Goma, eastern Congo, which has reserves of minerals that are needed by the world’s electronics giants © AFP/ Rwanda’s stealth occupation of eastern Congo on x (opens in a new w

Congo has severed diplomatic ties with Rwanda as fighting between Rwanda-backed rebels and government forces rages around the key eastern city of Goma.

The United Nations expressed deep concern at reports of M23 rebels and Rwandan troops advancing south towards the Congolese city of Bukavu on Thursday, as the militants sought also to assert their control over east Congo's largest city Goma.