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.

Rwanda-backed M23 rebels have expanded their presence in eastern Congo, capturing Goma, the region's major city. The UN expressed concerns over recent executions by the rebels following their intensified rebellion.

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