U.S. troops and the Russian military have been nearly operating side-by-side in the African country of Niger for several weeks as tensions over fighting Islamic extremists heat up in the region, officials said.

Russian military personnel have entered an air base in Niger that is hosting US troops – a move that follows a decision by Niger's junta to expel Amercian forces from the country. Niger's ruling junta has told the US to withdraw its nearly 1,