A de facto ceasefire between Congolese forces and Rwandan-backed rebels in the eastern Congo town of Walikale appeared to have broken down on Monday, with the rebels going back on a pledge to withdraw and accusing the army of violating its own commitments.

Rwanda-backed rebels battling Congo’s army have pushed into a strategic, mineral-rich town in the east, ignoring calls for a ceasefire this week by the Congolese and Rwandan presidents as the M23 rebel group expands its footprint in the conflict-torn African country.

M23’s success comes after a surprise meeting between the presidents of Congo and Rwanda in Qatar, where they pledged to ease tensions.