JERUSALEM – An anti-tank missile fired from the Gaza Strip struck a school bus in southern Israel Thursday, wounding two people, one of them critically, and prompting fierce Israeli retaliation that killed five Palestinians. Israel unleashed airstrikes and tank fire against Hamas targets across the border. It was the heaviest assault on the coastal territory since a broad military offensive two years ago. Besides the dead, more than 30 Palestinians were wounded, said Palestinian health official Adham Abu Salmiya. He said one of the dead was a 50-year-old civilian who was sitting outside his home when he was struck by...