The Organisation for the Prohibition of Chemical Weapons has confirmed that a war crime was committed on a rebel-held town of Khan Sheikhoun in north-western Syria on April 4.
According to a report released Friday, the OPCW found that sarin or a sarin-like substance was used in an attack that killed more than 80 villagers, including children.
Sarin is a clear, colorless and tasteless nerve gas that is highly toxic and harmful when exposed to it in high doses, according to the Centers for Disease Control and Prevention.
It is still unknown who committed the attack. The United Nations Director-General issued this statement in response to the report:
"I strongly condemn this atrocity, which wholly contradicts the norms enshrined in the Chemical Weapons Convention."
The Director-General added: "The perpetrators of this horrific attack must be held accountable for their crimes. In this context, the work of the Joint Investigative Mechanism assumes high importance.”
Days after the attack, the United States launched a military strike against Syria. The White House says Syria could be planning another chemical weapons attack.