Rwanda-backed rebels claimed on Monday 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.

The Rwandan-backed M23 rebels have released captured Romanian mercenaries who were fighting with the Congolese army. As they passed a border, they were chastised by Willy Ngoma, who tapped them mockingly one by one.

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.