Several chemical attacks occurred in different areas of Syria, including Khan al-Assal, Jobar, Saraqib, Ashrafiyat Sahnaya, Kafr Zita, Talmenes, Sarmin and Douma.
[5] Investigations have found that both the Ba'athist government of Bashar al-Assad and ISIL militants have used chemical weapons, with the vast majority of attacks being carried out by the Assad regime.
[6] Investigations launched by the UN's Independent International Commission of Inquiry on the Syrian Arab Republic concluded that the government of Bashar al-Assad carried out 33 chemical attacks between 2013 and September 2018.
"[6] The Khan Shaykhun chemical attack on 4 April 2017 drew international condemnation, and resulted in U.S. military action against the Ba'athist Syrian-controlled airbase at Shayrat.
"[13] Journalist Patrick J. McDonnell wrote in the Los Angeles Times in May 2013: "The Syrian government does not publicly acknowledge that it possesses chemical weapons, although international experts say it has a large arsenal, including sarin.
Specifically, Obama said: "We have been very clear to the Assad regime, but also to other players on the ground, that a red line for us is we start seeing a whole bunch of chemical weapons moving around or being utilized.
[20] On 28 September 2012, US Defence Secretary Leon Panetta said that the Syrian government had moved its chemical weapons in order to secure them from approaching opposition forces.
[24][25][26] Brigadier General Mustafa al-Sheikh, a Syrian army defector, confirmed that most of the chemical weapons have been transported to Alawite areas in Latakia and near the coast.
[30] Hours after Kerry's statement, the Russian foreign minister Sergey Lavrov announced that Russia had suggested to Syria that it relinquish its chemical weapons.
[33] Prior to September 2013 the Syrian government had not publicly admitted to possessing chemical weapons, although Western intelligence services believed it to hold one of the world's largest stockpiles.
[34] On 17 August 2017, Reuters published a report detailing the extent of Syria's failure to abandon chemical weapons, citing information from investigators, inspectors and diplomatic sources.
[35] Investigation conducted by Dr. Tobias Schneider and Theresa Lutkefend of the GPPi research institute documented 336 confirmed attacks involving chemical weapons in Syria between 23 December 2012 and 18 January 2019.
or 107[119] "The suspected chlorine attack marked the highest casualty toll in Aleppo since government forces and their allies clawed back the city from rebels nearly two years ago.
[48] In March 2017, the Commission documented conclusive evidence that Syrian aircraft dropped “toxic industrial chemicals, including chlorine,” between 21 July and 22 December 22, during the final period of the Battle of Aleppo (2012–2016).
[128] Investigations launched by the UN's Independent International Commission of Inquiry on the Syrian Arab Republic concluded that the government of Bashar al-Assad carried out 33 chemical attacks between 2013 and September 2018.
[38] Churkin said the chemical agent was carried by a "Bashair-3 unguided projectile", which was produced by the Basha'ir al-Nasr Brigade, a rebel group affiliated with the Free Syrian Army.
[133] On 27 May 2014, members of the mission were ambushed and briefly held by gunmen in rebel-held territory as it headed toward Kafr Zita to investigate the alleged chlorine gas attacks.
[136][137] On 7 August 2015, the United Nations Security Council adopted resolution 2235 (2015) to establish a joint investigation mechanism (JIM) to identify the perpetrators responsible for the use of chemical weapons in Syria.
[143] In late 2017, the JIM released its report on the April Khan Shaykhun chemical attack, attributing responsibility for the incident to the Syrian government.
[147][148] On 8 April 2020, the OPCW Investigation and Identification Team (IIT), set up in 2018, issued its first report, determining that the Syrian Air Force was the perpetrator of the chemical weapon attacks in Latamenah.
[149] On 12 April 2021, the OPCW IIT released a second report, which concluded that there were reasonable grounds to believe that the Syrian Arab Air Force carried out a chlorine attack on eastern Saraqib on 4 February 2018.
[a] In February 2012 a defector from the Syrian Army, a lieutenant who worked in the chemical weapons department, told Turkish newspaper Hürriyet Daily News that "BZ-CS, Chlorine Benzilate, which damages people's nerves and makes them fade away, is being used in Baba Amr."
[153] In December 2012, the Syrian government claimed that chemical plant SYSACCO 29 kilometers (18 mi) east of Aleppo was taken by rebel fighters from the Al-Nusra Front.
[156] On 4 June, the French foreign minister Laurent Fabius similarly declared certainty that the Syrian government had used sarin on multiple instances.
[161] In September 2015 a US official stated that ISIS was manufacturing and using mustard agent in Syria and Iraq, and had an active chemical weapons research team.
[164] On 8 April 2016, a spokesman for the Jaysh al-Islam rebel group said that “weapons not authorized for use in these types of confrontations” had been used against Kurdish militia and civilians in Aleppo (160 killed or wounded).
[168][165] On 4 May 2017, the BBC reported that, according to a Western intelligence agency, Syria was violating the 2013 disarmament deal by producing chemical and biological munitions at Masyaf, Dummar, and Barzeh.