Fears grow for Iraqi civilians held hostage near Mosul after mass execution of more than 200 people
A former Islamic State fighter says the group is shooting women and children fleeing areas under their control to deter others from escaping.
Abu Ahmed, who is now a prisoner of the Kurdish authorities, told Sky News he had been given orders to shoot to kill.
"People tried to flee, because of the conditions in Mosul, to Kurdistan or Baghdad but they would be blown up by IEDs and if they weren't they'd be shot at even if they were kids," he said.
"The thing people care about the most is their children, the hardest thing for anybody to see is their child being hurt even if it's not with a weapon but IS are going to use guns on children."
There are more than a million civilians trapped inside Mosul and many of them are being used as human shields.
The UN human rights office also said on Friday it received reports of more than 200 people being killed for refusing to follow orders from ISIL, also known as ISIS, or previously belonging to Iraqi security forces.
"ISIL's depraved, cowardly strategy is to attempt to use the presence of civilian hostages to render certain points, areas, or military forces immune from military operations - effectively using tens of thousands of women, men and children as human shields," UN spokeswoman Ravina Shamdasani said in Geneva.
Iraq launched a massive operation on October 17 aimed at retaking Mosul, which fell to ISIL in a matter of days in the summer of 2014. Iraqi forces are advancing from several directions, but are still outside the city itself.