Roughly half of Jordan's 5.5 million population is Palestinian. A Gaza-style civil war in the neighboring West Bank could spark clashes between the factions' supporters in the kingdom _ particularly in refugee camps where many support Hamas, the official said. The fighting is a major blow _ if not a death knell _ to months of attempts by U.S. Arab allies Egypt, Jordan and Saudi Arabia to unify the Palestinians and allow a resumption of the peace process with Israel. The three regional powers have backed Abbas while trying to moderate Hamas, and Egypt and Jordan have helped train Abbas' security forces.