Syrian regime forces carried out a gas attack on the opposition town of Douma on April 7, 2018, that killed 43 people, and Russian forces co-ordinated with them before and afterwards, according to the global chemical watchdog.

In a January report, the Organisation for the Prohibition of Chemical Weapons (OPCW) said a Syrian army helicopter dropped toxic chlorine gas cylinders on civilian areas on the Eastern Ghouta town of Douma, outside Damascus.

There are "reasonable grounds" to conclude the Syrian Air Force perpetrated the chemical weapon attack, it said.

The report was based on 70 environmental and biomedical samples, 66 witness statements and other data including forensic analysis, satellite images, gas dispersion modelling and trajectory simulations, the OPCW said.

"The use of chemical weapons in Douma -- and anywhere -- is unacceptable and a breach of international law," said OPCW director-general Fernando Arias.

On April 12, 2021, the OPCW reported its findings on another chemical attack that its Investigations and Identification Team (IIT) had determined was perpetrated by the Syrian regime.

The IIT "concludes that units of the Syrian Arab Air Force used chemical weapons in Saraqeb on February 4, 2018", it said.

The IIT, which also released the report on Douma, was established by member states in November 2018, after Russia vetoed a joint United Nations (UN) and OPCW mission to Syria.

Russia-Syria co-ordination

Although investigators modeled tens of thousands of possible trajectories for two yellow cylinders that appeared in photographs shortly after the April 2018 strike, they were unable to examine the weapons themselves, the OPCW report said.

The Syrian government notified the OPCW in 2019 that it had destroyed the containers, and "the destruction of the cylinders has precluded any further assessment or analysis for the purposes of the present report", it said.

The OPCW said it had received credible information that the helicopter squad that departed from Dumayr air base on April 7, 2018, was likely under the control of one of Syria's top military officers, the Washington Post reported.

The attack, allegedly carried out by a team led by then-Brig. Gen. Suheil al-Hassan, swiftly became part of a Russian disinformation campaign, which has been dismissed by the OPCW, the newspaper said.

While the report found no evidence of direct Russian involvement in the attack, it described Moscow's close co-ordination with Syrian forces in Douma before and after, as well as aggressive efforts to shield Syria from blame, it added.

The United States, United Kingdom, France and Germany issued a joint statement on January 27, after the OPCW report was released, condemning "in the strongest terms the Syrian regime's repeated use of these horrific weapons".

They reiterated their demand that the regime of Bashar al-Assad "immediately comply with its obligations under the Chemical Weapons Convention and relevant UN Security Council resolutions".

The OPCW report makes a thorough case for the al-Assad regime's responsibility for the attack, said the US State Department's undersecretary for Arms Control and International Security, Bonnie Jenkins.

"It also describes how closely the Syrian regime and Russia were co-ordinating at the time of the attack," she said.

The Syrian army's 25th Division ("Tiger Division"), commanded by al-Hassan, is affiliated with the Russian army, activists told Al-Mashareq. The Russian army was responsible for the siege of Douma prior to its fall to the Syrian regime.

Accountability for senior officials

The chemical attack on Douma "could not possibly have been perpetrated without the approval of higher commands, even if they deny it", said Cairo University professor of international criminal law Wael al-Sharimi.

He called for the case to be brought before the International Criminal Court (ICC) in the Hague, but noted that "the prosecution may not settle for trying only the four individuals mentioned in the report".

The case may be expanded "to hold their superiors accountable, all the way up to the Syrian president, as he is the Commander-in-Chief of the Armed Forces", al-Sharimi said.

He also noted that the Syrian regime is known to receive orders on military operations from Russian forces.

Syrian lawyer Bashir al-Bassam said the issue may be subject to investigation once again, as Russia is accused of being involved in the attack.

"A number of activists and media professionals have started preparing for the new case already, in the event that it reaches the ICC," al-Bassam said.

Douma was under the control of Syrian opposition forces, he explained, "and it was suffering from a stifling siege imposed by the Russian forces, their affiliated militias, and some Syrian army divisions".

"But the orders for shelling and raids came from the Russian operations room."

Justice for the victims

The images of the victims of the Douma chemical attack still haunt the Syrian people, Eastern Ghouta activist Mohammed al-Beik told Al-Mashareq.

He stressed the need to hold the perpetrators accountable for their actions.

Al-Beik praised the tireless work of the media and activists who documented the crimes at the time, noting that without these efforts, the OPCW's report would not have been possible.

In his opinion, he said, the most important outcome of the report is to reveal the truth about al-Assad's regime and the heinous crimes it has committed and continues to commit against the Syrian people.