In Jenin the battle was much harder and fierce. Unlike in Nablus, the forces who fought in Jenin were mainly reserve forces. The Palestinian militants booby-trapped the city and the refugee camp with thousands of explosive charges, some were very large and most were concealed in houses and on the streets. After 13 Israeli soldiers were killed in an ambush combined with booby traps, snipers and suicide bombers, the IDF changed its tactics from slow advancing infantry soldiers backed by attack helicopters to a heavy use of armoured bulldozers. The heavily armoured bulldozers began by clearing booby traps and ended with razing many houses, mainly in the center of the refugee camp. The armoured bulldozers were unstoppable and impervious to Palestinian attacks and by razing booby-trapped houses and buildings which used as gun posts they forced the militants in Jenin to surrender. In total, 56 Palestinians and 23 Israeli soldiers were killed in the battle of Jenin.