PORT-AU-PRINCE, Haiti (AP) — Students often throw up or wet themselves when gunfire erupts outside their school in northern Port-au-Prince.

When they do, school director Roseline Ceragui Louis finds there’s only one way to try to calm the children and keep them safe: getting them to lie on the classroom floor while she sings softly.

“You can’t work in that environment,” she said. “It’s catastrophic. They’re traumatized.”

Haiti’s capital is under the onslaught of powerful gangs that control 80% of of the city.