KABUL, Afghanistan (AP) — The top U.S. commander in Afghanistan is handing over his authority at a ceremony as America winds down its 20-year military presence and Taliban insurgents continue to gain territory across the country.

Gen. Scott Miller was poised to transfer authority to Gen. Frank McKenzie, the head of U.S. Central Command.

McKenzie also is a four-star general. He will operate from Central Command headquarters in Tampa, Florida, assuming authority to conduct possible airstrikes in defense of Afghan government forces.

The U.S. withdrawal was to conclude Aug. 31. Miller was to leave the country later Monday.

The handover comes as Taliban insurgents make territorial gains across Afghanistan. The Associated Press found the group has control of more than a third of the country’s 421 districts and district centers.

Miller’s departure will reportedly not reduce the scope of the U.S. military mission in the Middle Eastern country.