The Islamic State militants arrived at Khalida Abd Jamal’s house through holes they cut in the concrete walls. Holding a gun to her husband’s head, they corralled the family of seven into a room on the first floor.

“We were stuck in the room,” she recalled. “We had to stay. We couldn’t leave.”

Through a window, she could see a sniper positioned on top of another house in her west Mosul neighborhood of Jadidah.

Moments later, a massive explosion leveled her entire block, killing scores of civilians. The source of the attack remains under investigation, but witnesses said it was an airstrike by the U.S.-led military coalition trying to drive the militants out of the city.

Jamal and her immediate family survived. The account she gave supports the assertion by some officials that the terrorist group is using a new tactic to turn the population in Mosul against the coalition: Herding civilians into houses, then stationing snipers on the rooftops to provoke airstrikes.