Niger's decision to end its counterterrorism alliance with Washington came after senior U.S. officials accused the country's ruling junta of secretly exploring a deal to allow Iran access to its uranium reserves, Nigerien and U.S. officials say. The decision to end military cooperation with the U.S. was announced Saturday night by a spokesman for the Nigerien junta. It deals a serious blow to the Biden administration's efforts to contain a sprawling Islamist insurgency in the Sahel, the semiarid region south of the Sahara.