By 1:00 pm, the Americans were from the fort, and their artillery and the naval squadron were preparing to bombard it. Pike was questioning a prisoner as to how many troops were defending the fort. Shortly after the bombardment began, the magazine (which contained over 74 tons of iron shells and 300 barrels of gunpowder and had been rigged by the British to explode) blew up. The explosion threw debris over a radius. General Pike and 37 other American soldiers were killed by the explosion, which caused an additional 222 casualties. Fearing a counterattack after the explosion, American forces regrouped outside the wall, and did not advance onto the abandoned fort until after the British regulars had left the settlement.