BAGHDAD — By 1 p.m. on Friday almost every Christian in Mosul had heard the Sunni militants’ message — they had until noon Saturday to leave the city.

Men, women and children piled into neighbors’ cars, some begged for rides to the city limits and hoped to get taxis to the nearest Christian villages. They took nothing more than the clothes on their backs, according to several who were reached late Friday.

The order from the Islamic State in Iraq and Syria came after Christians decided not to attend a meeting that ISIS had arranged for Thursday night to discuss their status.

“We were so afraid to go,” said Duraid Hikmat, an expert on minorities who had done research for years in Mosul. He fled two weeks ago to Al Qosh, a largely Christian town barely an hour away, but his extended family left on Friday.