Soldiers from 1st Battalion, 503rd Parachute Infantry Regiment (PIR), 173rd Infantry Brigade Combat Team (Airborne) pulls security after an air assault practice operation during exercise Immediate Response 19 at Udbina Airbase, Croatia, May 17, 2019. IR 19 continues to increase participating nations’ capacity to conduct full spectrum military operations. Exercising joint forcible entries enhances the force’s ability to seize key terrain quickly in order to build combat power.