The battle was fought by both sides as a World War I Western Front style battle, with each side launching bloody frontal assaults on enemy positions in what became a war of attrition. The Nationalist tactic was to use artillery and aerial bombardment in small areas to soften resistance and then to launch a frontal assault with one or two infantry battalions to occupy the area. Each day 500 cannons fired more than 13,000 rounds at the Republican troops and more than 200 Nationalist aircraft dropped 10,000 pounds of bombs. Nevertheless, the Republican troops fought with stubborn bravery and repelled the Nationalist assaults with barrages of machine-gun and mortar fire. In many zones, the terrain was too hard to dig trenches or foxholes, and as the August heat became unbearable (on 4 August it was 37 degrees in the shade), the shortages of water and food grew worse for the Republican troops. The situation was made more desperate by the relentless bombing that the Republican troops endured from dawn to dusk, which made it impossible for bodies to be buried, and meant that the wounded could only be evacuated at night, by small boats.