A sapper, also called pioneer or combat engineer, is a combatant or soldier who performs a variety of military engineering duties such as bridge-building, laying or clearing minefields, demolitions, field defences and general construction, as well as road and airfield construction and repair. They are also trained to serve as infantry personnel in defensive and offensive operations. A sapper's duties are devoted to tasks involving facilitating movement, defence and survival of allied forces and impeding those of enemies.