Israeli airstrikes pounded Gaza early Friday in what appeared to be the heaviest attacks since clashes erupted at the start of the week.Masses of red flames illuminated the skies as the deafening blasts from the outskirts of Gaza City jolted people awake.Late Thursday, Israel fired tank and artillery shells across the border for the first time in the current round of fighting, sending scores of terrified residents fleeing for safety.Israel said it was massing troops along the Gaza frontier and calling up 9,000 reservists ahead of a possible ground invasion of the Hamas-ruled territory.
