UN Chief Ban vists UNRWA school in Gaza REFILE TO CORRECT 5.5 TO 5.4 IN SOUNDBITE 3United Nations chief Ban Ki-moon made a brief visit Tuesday to war-ravaged Gaza, two days after donor states pledged $5.4 billion in aid to rebuild it after a devastating Israeli offensive. In Jabaliya, he visited a UN school where in July shells slammed into two classrooms, killing at least 14 people sheltering there. IMAGES AND SOUNDBITES