Qatari international media giant Al Jazeera has threatened that it will be imminently suing a Russian propaganda outlet for defamation after it was accused of staging a chemical weapons attack against civilians in Syria last month that drew a cruise missile strike in response from the United States.

Russia’s state-owned news agency Sputnik published a story yesterday claiming that the Syrian sarin gas attack last month on Khan Sheikhoun village in Idlib province was a “false flag” operation by Qatar’s Al Jazeera network, allegations that the channel vehemently denied.

Sputnik claims the information came from a “military and diplomatic source” and that it was “confirmed via several channels,” but it did not identify them.

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Sputnik’s article said that about “30 fire engines and ambulances, as well as 70 local residents with children transported from a refugee camp were used in the filming across three locations in Idlib province…”. It cited anonymous sources for the claim.

Al Jazeera responded on its website, saying: “Sputnik is just a propaganda tool that publishes fake news without any shame and this has been cited by several study centres and media outlets.”

“It is known that Sputnik is always used as a propaganda tool to defend the Syrian regime on an ongoing basis,” and that it had published earlier reports denying the chemical strike in Khan Sheikhoun, calling it “fake and staged,” even though the attack was confirmed by other impartial agencies and the Independent International Commission of Inquiry, Al Jazeera said.

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Al Jazeera said that it will take legal action against the Russian news network, and warned that it was concerned that Sputnik itself may have been a “conspirator” in chemical weapons attacks against civilians:

Finally, Al Jazeera would like to highlight to the international community its concern that if a chemical attack was launched, as it was described in Sputnik’s fabricated article, then the Russian agency would be considered to be a conspirator with those involved.

A US report said that the chemical agent was delivered by a Syrian Su-22 fixed-wing aircraft that flew over the village of Khan Sheikhoun at the time of the attack, which killed at least 87 civilians, including 31 children, on 4 April.

“Additionally, our information indicates personnel historically associated with Syria’s chemical weapons programme were at Shayrat airfield in late March making preparations for an upcoming attack in northern Syria, and they were present at the airfield on the day of the attack,” the US government report said.

Washington’s conclusions relied on satellite imagery, laboratory analysis of physiological samples from victims and a “significant body of open source reporting” that the report says could not have been fabricated.