An unconscious Syrian child receives treatment at a hospital in Khan Sheikhun, a rebel-held town in the northwestern Syrian Idlib province, following a suspected toxic gas attack on April 4, 2017.

A suspected chemical attack killed at least 58 civilians including several children in rebel-held northwestern Syria, a monitor said, with the opposition accusing the government and demanding a UN investigation. / AFP PHOTO / Omar haj kadour        (Photo credit should read OMAR HAJ KADOUR/AFP via Getty Images)