Jenin CNN  —  For more than a week, the sprawling Jenin refugee camp in the occupied West Bank has echoed to the sound of heavy gunfire – with masked snipers on roof tops and muffled explosions within its warren of alleyways. But the combat has not involved the Israeli military, which has launched countless raids in recent years against what it calls terrorists in the camp, a stronghold of resistance to the Israeli occupation. This fight is between Palestinians: the security forces of the