DAKAR, Senegal (AP) — Rebels in Congo say the United States has fallen short as a mediator in efforts to end the conflict in the African country’s mineral-rich east as the Trump administration seeks to open the region’s critical reserves to the U.S. government and American companies . According to a letter to U.S. Secretary of State Marco Rubio from Congolese rebel leader Corneille Nangaa, Washington has failed to pressure Congo’s government over its alleged violations of peace commitments. The