<span style="color: #222222;">US Army General Austin Miller has assumed command of the 41-nation NATO mission in Afghanistan following a handover ceremony. </span><br />'' <br />'' <span style="color: #222222;">Miller took over Sunday from General John Nicholson, who held the post for more than two years, at a ceremony attended by senior Afghan officials and foreign ambassadors in Kabul.</span><br />'' <br />'' <span style="color: #222222;">The handover comes at a time when Afghan forces are struggling to contain a resurgent Taliban and an increasingly powerful Islamic State affiliate. </span><br />'' <br />'' <span style="color: #222222;">The Taliban control several districts across Afghanistan, and both groups have launched a relentless wave of attacks in recent months.</span><br />'' <br />'' <span style="color: #222222;">The NATO mission began with the U.S.-led invasion that toppled the Taliban after the September 11 attacks. The U.S. and NATO formally ended their combat mission in 2014 but still routinely come to the aid of Afghan forces.</span><br />