The leader of a Congolese rebel coalition that includes the M23 group says a deal between Kinshasa and Washington related to critical minerals in the war-hit region was deeply flawed and unconstitutional, casting doubt on its implementation. Most of eastern Congo’s key minerals, including coltan, lie in areas now held by M23, which has seized major mining zones such as Rubaya in North Kivu. Asked for comment, the Congolese presidency rejected Nangaa’s accusations, saying the partnership “fully falls within the constitutional prerogatives” of the elected president and government. The U.N. Human Rights Office says M23, Congolese armed forces and other armed groups have committed serious rights violations, some of which may amount to war crimes. M23 forces briefly entered the town of Uvira in December saying it sought to stop attacks on civilians, but later withdrew.