The United States, France and the UK all blamed a suspected chemical attack in the Syrian town of Douma on the Assad regime.
All three countries took military action in response on Saturday, firing 105 missiles at regime-controlled installations and chemical weapons facilities near the Syrian capital.
While Russia claimed 71 were shot down, the U.S. said all of its missiles successfully struck their targets without interception by Syrian air defenses. On Sunday, chemical weapons investigators arrived in Douma to examine the site of the suspected attack.
Even though Douma and the military retaliation that followed it focused global attention on chemical weapons usage in Syria, it was by no means the first such attack since civil war erupted in the country.
An attack on Khan Shaykhun in April 2017 resulted in the U.S. firing 59 Tomahawk cruise missiles at Shayrat Airbase. Human Rights Watch has claimed that there have been 85 chemical attacks across the country since 2013 while the Independent International Commission of Inquiry on the Syrian Arab Republic has confirmed 34 incidents.
Three of the confirmed attacks involved sarin while 26 are suspected to have involved chlorine. The chemical used in a further five attacks was not specified.
According to U.S. administration officials, the attack on Douma involved the use of both sarin and chlorine. They said eye witnesses reported seeing government helicopters flying over the town while photo and video evidence exists of the remnants of chlorine barrel bombs.
Video and photographic evidence also shows symptoms associated with exposure to chlorine while doctors and aid organizations on the ground have also reported consistent with exposure to sarin as well as a strong smell of chlorine.
This article and chart originally appeared on the blog of statistics firm Statista, and is republished here with permission.