Israel struck hard into the Gaza Strip by land and air on Friday, trading fire with gunmen in fighting that killed eight Palestinians including a 12-year-old boy, Palestinians said. The deaths drove the Palestinian death toll to 16 in Israeli raids since a terror attack killed two Israeli civilians at a border fuel depot Wednesday, where Israel pumps vital supplies into Gaza. Prime Minister Ehud Olmert has pledged to keep hitting Hamas so that it cannot "continue to operate against Israeli civilians as it does." By Friday evening, Gaza residents said the ground fighting appeared to be easing, although there were still exchanges of Palestinian rockets and Israeli helicopter fire in which a Hamas gunman was killed. Also Friday, IDF soldiers, accompanied by tanks and bulldozers, operated in central Gaza, close to the El-Bureij refugee camp. The IDF said that there had been exchanges of fire with armed Palestinians in the area, stating that gunmen had been hit. No further details were announced. The army also reported that a number of mortar shells were fired by Palestinians, with no casualties reported. On Thursday night, two Hamas gunmen were killed when they were targeted in two IAF strikes near Khan Yunis, in the southern Gaza Strip, Palestinian officials reported. Seven other Palestinians were wounded in the attacks, they said. An IDF spokesman confirmed the air raid, saying the air force targeted and hit gunmen.