Pentagon Hands Over Last Base in Niger as Extremism Spreads in the Sahel

The U.S. military turned over control of its last base in Niger to local forces on Monday, ending a yearslong counterterrorism mission in the West African country even as violent extremism remains on the rise in the region.

A group of U.S. troops boarded an Air Force cargo plane and flew out of a $110 million air base in central Niger that was built with Pentagon money, among the last of 1,000 personnel that Washington had agreed to pull out by Sept. 15. A small number of troops will remain at the United States...