Hamas and Fatah, the two main Palestinian factions, battled each other again this week in Gaza and the West Bank. Hamas, the ruling Islamist party that controls Gaza, killed a Fatah colonel and seven others there. Fatah, which controls the West Bank, wounded two Hamas supporters and kidnapped an official. Over the weekend, President Mahmoud Abbas, who heads Fatah, declared Hamas militia, which is funded by Iran, illegal, while Abbas deputy, Mohammad Dahlan, held a massive Fatah rally in a Gaza soccer stadium. If anyone from Fatah is attacked, we will hit back twice as hard, Dahlan said. Over the last month, fighting between Hamas and Fatah has claimed more than 30 lives.