Russian officials said on Friday that their government can prove beyond a shadow of a doubt that a suspected chemical attack on a rebel-held enclave in Syria last week was a hoax staged by British spies. The defense and foreign ministry officials declined, however, to say what the evidence was, or expose it to public scrutiny. That matters because Russian officials have a history of making false or misleading claims about attacks in Syria based on internet conspiracy theories or hoaxes. Volunteer rescue workers and antigovernment activists in Syria said that more than 40 people were killed in a chemical attack in Douma, east of Damascus, on Saturday, and shared images of the dead and wounded on social networks. With the United States and Britain considering military strikes on the forces of Syrian President Bashar al-Assad to deter the use of chemical weapons, Russia seemed to go all-out on Friday to shield its Syrian ally. “We have irrefutable evidence that this was another staged event,” Foreign Minister Sergey Lavrov told reporters in Moscow, “and that the secret services of a certain state that is now at the forefront of a Russophobic campaign was involved in this staged event.” That Lavrov was accusing Britain of carrying out false-flag attack was clear, since Russian diplomats have repeatedly claimed that another recent chemical attack — the poisoning of Sergei Skripal, a former Russian-British double agent living in England — was also staged by British spies in order to frame Russia. Russian Defense Ministry spokesperson, Maj. Gen. Igor Konashenkov, made the accusation explicit, telling reporters later that Russia’s military had “evidence that proves Britain was directly involved in organizing this provocation.” Russian officers in Syria, Konashenkov said, visited Douma after rebels surrendered control of the suburb on Sunday and could find no trace of any chemical agents at the site of the bombing. They did, however, interview two medics there who said that video of the attack survivors being treated for exposure to chemicals had been faked by armed men with cameras who burst into the hospital. Video testimony from the two medics, displayed on a giant screen behind the Russian spokesperson, was presented as proof that the attack had been a hoax in an Arabic-language tweet from the ministry.

At the news conference where it was presented, the testimony of the two men could not be properly evaluated, however, because the ministry showed video of them speaking, but did not play the audio of what they said.

Late Friday, the video of the two men — bearing the copyright of MIL.RU, the Russian defense ministry’s website — was posted online by the Kremlin-run news site Sputnik. It was difficult to tell if the report produced by the Russian military, in an area of the country that had been outside the Syrian government’s control for years, recorded the genuine impressions of what the Douma hospital workers had witnessed, or was more akin to the kind of forced confessions that aired on Iranian state television after the post-election protests in 2009.

Konashenkov also claimed, without citing evidence, that “London” had directed a group of volunteer rescue workers, known as the White Helmets, “to stage a provocation with an alleged use of chemical weapons.” Russian diplomats and pundits on state-controlled news outlets have, for years, promoted unverified conspiracy theories about the White Helmets working with Islamic extremists and foreign intelligence agencies. Attempting to discredit the rescue workers, who often film in the immediate aftermath of bombings by government forces or Russian jets, has been a central concern for supporters of the Syrian government since the protest movement of 2011 turned into an armed conflict.

.@MoD_Russia: a fake “chemical weapons massacre” was a last attempt to stage a provocation for the benefit of extremists and their foreign backers. pic.twitter.com/ErHztaSEfY — Russian Embassy, UK (@RussianEmbassy) April 12, 2018

Britain’s ambassador to the United Nations, Karen Pierce, rejected the claim that her country’s foreign intelligence service had staged a fake chemical attack. “This is grotesque, it is a blatant lie,” Pierce said, “it is the worst piece of fake news we’ve yet seen from the Russian propaganda machine.” Given that Douma is now under the control of the Assad government, Russia’s ally, and thus off-limits to independent journalists, the Russian claims are impossible to verify or debunk — a situation Russian and Syrian officials have taken advantage of throughout the war to cast doubt on claims that atrocities have been committed by forces loyal to Assad. However, the last time Russia claimed to have evidence of secret collaboration between a Western government and Islamic extremists in Syria, that proof was quickly shown to be fake. As Eliot Higgins explained on the open-source investigations site Bellingcat in November, the Russian defense ministry claimed that month to have uncovered “irrefutable evidence” of cooperation between the U.S. military and Islamic State militants. However, images offered as proof on the ministry’s various Twitter feeds were identified within hours as screenshots taken from a video game and clips of Iraqi combat operations against ISIS fighters.

Reminder that the last time Russia claimed "irrefutable evidence" of something in Syria they used pics from a computer game and year-old footage pic.twitter.com/VtbtflaVtr — Alastair Reid (@ajreid) April 13, 2018