The suspected use of chemical weapons in Damascus may be an international turning point but, as Channel 4 News examines, it is not the first time such attacks have been alleged in Syria’s civil war.
Warning: the interactive map below contains graphic images and links to videos you may find distressing. Channel 4 News includes it because of the importance in understanding what is alleged to be happening in Syria. Much of the footage is amateur video which has not been independently verified.
(Explore the map above to see the site of alleged chemical weapons attack, and chemical facilities. Warning – includes distressing images and links to extremely distressing video footage. Map image credit: Bing)
The alleged attack in Damascus on Wednesday 21 August has been condemned across the international community as “horrific” and “abhorrent“. It has led to talk of military intervention against Bashar al-Assad’s regime if it is proved, as many countries believe, to have been at his behest.
Distressing footage that emerged following the attack shows victims of the alleged chemical; weapons use showing symptoms such as twitching limbs, dilated pupils and forthing at the mouth (warning – link directs to page including distressing footage).
The attack has prompted David Cameron to recall parliament in order to discuss what the British response should be.
Read more: Syria - the military options
The Syrian government has allowed UN inspectors access to the sites of the suspected attack, which is reported to have targeted rebel strongholds in the east and south west of the Syrian capital.
But the UN inspectors were in Syria to investigate previous claims of chemical weapons attacks, including at Khan al-Assal, near Aleppo, where both the rebels and the Syrian government lay blame on their opponents in the bloody civil war.
Channel 4 News has catalogued, via unverified video posted on social media websites, claims that the Assad government has carried out 26 separate chemical weapons attacks.
At least 55 people are claimed to have been killed in these attacks, and nearly 600 injured. The claims date as far back as March 2012.
In turn the Assad regime has accused rebels of carrying out such attacks, including at Khan al-Assal but also more generally via news reports on Syrian state television.
Underpinning the use of chemical weapons are the chemical weapons facilities spread across Syria, but concentrated in Damascus.
Channel 4 News research has located 14 chemical weapons facilities across the country, including chemical and biological weapons laboratories, bases for missiles with chemical warheads, factories for the production of nerve agents such as sarin, underground bunkers and secret chemical storage facilities.
One of the main chemical weapons sites in Syria is at al-Safirah. The Syrian government has a heavily fortified complex of factories where chemical weapons, gas and gas masks are produced. The site also includes chemical and biological weapons laboratories, and shells and bullets are also manufactured here.
In Damascus facilities feature residences for Iranian and North Korean experts. One such facility, at Jomayrah, has been targeted three times by the Israeli airforce because of alleged links with Lebanese militant group Hezbollah.
International intervention in Syria is likely to depend on UN findings about chemical weapons abuse and the evidence awaits to be verified. What can be said for certain, however, is that for the people of Syria, the words “abhorrent” and “horrific” barely scrape the surface.