U.N. Secretary-General Ban Ki-moon is demanding an investigation into a strike on a school in Idlib, Syria, that killed 26 civilians, mostly children. Ban’s spokesperson said the attack could amount to a war crime.

Stéphane Dujarric: “The secretary-general calls for an immediate and impartial investigation of this and other similar attacks against civilians in Syria. If such horrific acts persist despite global outrage, it is largely because their authors, whether in corridors of power or in insurgent redoubts, do not fear justice. They must be proved wrong.”

Russia’s Defense Ministry denied that its warplanes were responsible for the attack. It released drone footage that it claimed showed the school was not struck from the air, and accused the Syrian Observatory for Human Rights and the Civil Defense Network, or “White Helmets,” of spreading propaganda. In Washington, a White House spokesperson said either Syrian or Russian warplanes were to blame.