A nurse traveling in an ambulance was shot in the head and killed after being caught in the crossfire, hospital officials said. Fighting raged close to Palestinian Authority Chairman Mahmoud Abbas's heavily guarded compound, which was also targeted by Hamas mortar fire overnight. Abbas was not present. Early Wednesday, Hamas gunmen fired mortars and pipe bombs at the home of Fatah security chief Rashid Abu Shbak, before storming inside, lining six Fatah bodyguards up against the wall and shooting them dead, Palestinian security and medical officials said.