Syrian civil war
Also, in 2013 the Syrian regime allegedly used chemical weapons, a nerve agent called sarin. This drew attention from the international community.  The US and Russia made Syria sign the Chemical Weapons Convention, which forbids the use of chemical weapons. The government reportedly surrendered their chemical weapons in 2014. In 2017, the town of Khan Shaykhun was hit by another sarin attack, which killed 90 people, and 30 of them were children.