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.

In his first public remarks since the M23 rebels advanced into eastern Congo’s largest city, Goma, on Monday, President Tshisekedi late on Wednesday vowed “a vigorous and co-ordinated response” to push back the rebels while reaffirming his commitment to a peaceful resolution.

Fighting across the largest city in eastern Democratic Republic of Congo and "is still very much ongoing ... it's not over yet," senior U.N. official in Congo, Bruno Lemarquis, said on Monday after Rwandan-backed M23 rebels claimed to have control of Goma.