Israel called on civilians to evacuate parts of Rafah on Monday in what appeared to be preparation for a long-threatened assault in the southern Gaza Strip city where more than a million war-displaced Palestinians have been sheltering. Instructed by Arabic text messages, telephone calls, and flyers to move to what the Israeli military called an “expanded humanitarian zone” 20 km (7 miles) away, some Palestinian families lumbered out under chilly spring rain, witnesses said. Israel’s military said it had begun “encouraging” residents of Rafah to evacuate in a “limited scope” operation. It gave …