Between 2 and 11 April, a siege and fierce fighting took place in the Palestinian refugee camp of the city of Jenin. The camp was targeted during Operation Defensive Shield after Israel determined that it had "served as a launch site for numerous terrorist attacks against both Israeli civilians and Israeli towns and villages in the area." The Jenin battle became a flashpoint for both sides, and saw fierce urban combat as Israeli infantry supported by armor and attack helicopters fought to clear the camp of Palestinian militants. The battle was eventually won by the IDF, after it employed a dozen Caterpillar D9 armored bulldozers to clear Palestinian booby traps, detonate explosive charges, and raze buildings and gun-posts; the bulldozers proved impervious to attacks by Palestinian militants.