U.S. Marines with the air interdiction force composed of 1st Battalion, 25th Marine Regiment, and 2nd Bn., 11th Marines, pause for a break as a CH-53 Sea Stallion refuels during an Afghan Border Police led clearing operation here, Dec. 7. The AIF circles high in sky above, searching for suspicious vehicles or personnel, and plays a unique role in counter-insurgency operations in southern Helmand. - U.S. Marines with the air interdiction force composed of 1st Battalion, 25th Marine Regiment, and 2nd Bn., 11th Marines, pause for a break as a CH-53 Sea Stallion refuels during an Afghan Border Police led clearing operation here, Dec. 7. The AIF circles high in sky above, searching for suspicious vehicles or personnel, and plays a unique role in counter-insurgency operations in southern Helmand.