They’re concerned that the Russian fighters — who are stationed at the same air base as American troops in the capital of Niamey — will engage in disruptive behavior such as driving aggressively or harassing U.S. troops at checkpoints, according to two officials familiar with Western intelligence.

Before a coup in Niger in July 2023 led to the demand that American troops leave the country, the U.S. had used the two bases to fly drones on counterterrorism missions across the vast Sahel region of north Africa, where political unrest and weak central ...