Security forces on Friday pulled out of a central Gaza refugee camp, ending a two-day military operation meant to flush out suspected terrorists and stop cross-border rocket fire. Meanwhile, a Hamas terrorist and three of his relatives were killed Friday in an explosion at his home in Gaza City. The cause of the blast was not immediately clear. Palestinians said that the house was hit by an Israeli tank shell, but the military denied using artillery or tanks. In the past, Palestinian gunmen have been killed while handling explosives. The latest withdrawal of troops from Gaza was followed by a 24-hour temporary respite in fighting on the front Saturday. The ongoing military operation was triggered by last month's daring cross-border Hamas raid in which two Israeli soldiers were killed and Cpl. Gilad Shalit was captured. More than 100 Palestinians - the vast majority of them gunmen - have been killed in Gaza since the operation began.