Nearly 1,000 civilians have fled the besieged city of Mosul, crossing the border into Syria, in the first known large group that’s been able to escape since Iraq began trying to liberate its second-largest metro area from control by the Islamic State terror group. More than 900 people are now at a refugee camp, according to a UN agency. Officials have expressed concerns that the 5,000 ISIS militants may try to use civilians as human shields to hold on to its Iraq stronghold. The Iraqi government told Mosul residents that it might be safer to remain in the area, because ISIS militants may have set up snipers and booby-trapped roads. The civilians reported that others had been prevented from leaving the city.