The leader of the rebels who captured two key cities in eastern Congo tells The Associated Press that international sanctions and Congo’s proposed minerals deal with the United States in search of peace will not stop the fighting.

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.

The country’s president offered a deal that would give the U.S. access to key minerals in return for a security pact that helps defeat the powerful M23 rebel force.