Khan Shaykhun chemical attack

The Khan Shaykhun chemical attack took place on 4 April 2017 on the town of Khan Shaykhun in the Idlib Governorate of Syria. The town was reported to have been struck by an airstrike by government forces followed by massive civilian chemical poisoning. The release of a toxic gas, which included sarin, or a similar substance, killed at least 89 people and injured more than 541, according to the opposition Idlib Health Directorate. The attack was the deadliest use of chemical weapons in the Syrian civil war since the Ghouta chemical attack in 2013.

The OPCW-UN Joint Investigative Mechanism attributed the responsibility of the attack to the Syrian government. The OPCW-UN JIM described chemicals that it said linked the sarin used to the Syrian government: "The samples from Khan Shaykhun contain the three types of marker chemicals described above: PF6 [HFP], isopropyl phosphates and isopropyl phosphorofluoridates. Their presence is a strong indicator that the sarin disseminated in Khan Shaykhun was produced from DF from the Syrian Arab Republic stockpile."

The governments of the United States, United Kingdom, Turkey, Saudi Arabia, France, and Israel as well as Human Rights Watch attributed the attack to the forces of Syrian President Bashar al-Assad. The Syrian government said the attack was a "fabrication" while the Russian government said that the incident was staged.

On 7 April, the United States launched 59 cruise missiles at Shayrat Air Base, which U.S. intelligence cited as the source of the attack.