An EU monitoring team collected 80 examples of disinformation from Russian sources in nearly two months up to 16 March. Coronavirus was claimed to be a biological weapon deployed by China, the US or the UK. Other conspiracy theories contended the outbreak was caused by migrants or was a pure hoax.

“Pro-Kremlin media outlets have been prominent in spreading disinformation about the coronavirus, with the aim to aggravate the public health crisis in western countries, specifically by undermining public trust in national healthcare systems,” states the report, seen by the Guardian.

The European commission’s chief spokesperson on foreign and security policy, Peter Stano, said there had been an increase in “disinformation, misleading information, outright lies and wrong things” since the start of the outbreak.

The commission had noticed, he said, an increase in disinformation from Russia, providers based in the country and those with links to pro-Kremlin sources.

One conspiracy theory aired on Kremlin-backed Sputnik radio in February drew a parallel between the 19th-century opium wars and coronavirus, implying that “England” and unnamed “international organisations” were seeking to control Chinese internal affairs, just as the British empire forced China to open its markets and cede territory at gunpoint.

Meanwhile, the website Ria Fan claimed that a “false panic” about Covid-19 would benefit pharmaceutical companies looking to make “lucre” from the virus. And against a soundtrack of menacing music, Ren TV’s Military Secret documentary claimed the virus could be a “biological weapon” disseminated by US special forces in China.

Researchers at Cardiff University’s centre for crime and security research, who carried out research with the commission, found an evolution in tactics by pro-Kremlin media.

Rather than authoring disinformation, Russian sources were amplifying theories that had originated elsewhere, such as China, Iran or the US far right, the researchers said. “This tactic allows them to avoid the accusation of creating disinformation themselves, claiming instead that they are merely reporting what others are saying,” the report stated.

Russia has strongly denied the accusations. “If there was even a single concrete example, I could comment on it, but once again they are just unfounded accusations,” said a spokesman for the Russian president, Vladimir Putin.

An internal EU network, where member states share cases, also reported examples of disinformation. In Lithuania there were false claims that a US soldier deployed to the country had been taken to hospital with coronavirus.

Slovak authorities reported false information about the prime minister, Peter Pellegrini, who was said to have had the virus and infected EU leaders at a Brussels summit in February. (Pellegrini posted a picture of himself from a hospital bed on Facebook on 23 February, saying he had “an extensive infection”.)

The report noted that the Kremlin-funded media company RT’s Spanish service was the 12th most popular source of information on coronavirus among social media users.

EU officials also commented on media narratives in other countries. In China, the report said, state media sought to depict Xi Jinping as doing an admirable job, while portraying China’s political system as an asset in tackling the virus. In Iran, Covid-19 was described as a US bioweapon, as well as a disease weaponised by Israel to target Iran.

The report concluded “the more pressing challenge” for public health was misinformation: stories that are inaccurate, often dangerously so, but not created with a political agenda.

The report referred to claims that a “miracle mineral supplement” could wipe out coronavirus, a dangerous falsehood promoted by one prominent YouTuber. The US Food and Drug Administration warned last year that ingesting this substance, which contains chlorine dioxide, was equivalent to “drinking bleach”.

The World Health Organization said last month the Covid-19 outbreak had been accompanied by an “infodemic”, an abundance of information, some accurate and some not. Facebook has since promised to give the WHO “as many free ads as they need” to turn the tide.

The European commission is asking social media companies to promote its content more actively.

The report concludes that social media companies have taken “strong measures” to combat false claims, but worries they are not doing enough to share information with independent observers. In particular, officials want to know how much time elapses between disinformation being posted and acted upon by social media companies.

“Whoever is spreading the disinformation is essentially playing with people’s lives,” Stano said. “Every responsible social media or media user should be aware of this: that there is a lot of misinformation circulating around … Double check, triple check, go to a media you really trust and look at the sources.”