In World War II amphibious assaults, naval warships would open fire with their main armaments at known or suspected enemy artillery, mortar, or machine gun positions, on or behind the landing beaches, to suppress enemy fire from these positions which could be directed against the landing troops. The rise of mass usage of aircraft and aerial assaults also gave rise to bombing runs and strafing runs, serving as oft-used means of suppressing enemy forces, disrupting enemy lines, and inflicting heavy damage on the enemy all at once, using concentrated fire from machine guns and/or carried-on explosives to pin down entire swathes of territory. Firebombs were also used for suppression, area denial, and extensive psychological effect. The Vietnam War and the commonplace implementation of napalm furthered this concept.