Brussels waded into the dispute between President Donald Trump and Twitter on Wednesday, backing the US social media giant's decision to fact-check two tweets by the US leader.
The European Commission's top official on countering disinformation praised Twitter for tagging two claims made by Trump last month about postal ballots in US elections.
The intervention came as the EU urged web giants including Twitter, Facebook and Google to do more to tackle the "massive wave" of harmful online disinformation triggered by the coronavirus pandemic.
Brussels officials said that while social media platforms had taken steps to counter the deluge of misleading healthcare information, hoaxes and conspiracy theories, their efforts were "not good enough".
Trump has come under fire for suggesting COVID-19 patients could be treated by ingesting disinfectant, but it was his tweets claiming mail-in voting would lead to a "rigged election" that sparked the clash with Twitter.
The site added links reading "get the facts" to the two Trump tweets, infuriating the social-media savvy president, who has more than 80 million followers.
Vera Jourova, the European Commission vice-president for values and transparency, who leads the bloc's anti-disinformation fight, said this was the right approach.
"I support the Twitter reaction to tweets of President Trump," she said. "They did not delete it. We all can see it. They provided fact-checked information and promoted facts."
Jourova was speaking at the launch of a major policy document outlining the EU's approach to tackling disinformation about the pandemic.
In the report, the bloc also accused China and Russia of mounting targeted propaganda campaigns to undermine democracy and burnish their own images.
"The pandemic showed that disinformation does not only harm the health of our democracies, it also harms the health of our citizens," said Jourova.
Since the outbreak of the pandemic, Twitter has challenged more than 3.4 million suspicious accounts targeting coronavirus discussions.
YouTube, which is owned by Google, has reviewed more than 100,000 videos related to misleading virus information and removed more than 15,000 of them,
Jourova welcomed these efforts but said more was needed, urging platforms to share more information.
"They have to open up and offer more evidence that the measures they have taken are working well," she told reporters.
After some platforms were accused of exploiting controversial content to drive revenue from adverts, Jourova said this business model needed to be examined.
"It is also crucial to remove the financial incentives for those who want to benefit from disinformation," she said.
False claims about how the virus originated and spread and how it can be treated have mushroomed as fast as COVID-19 has spread around the globe.
They include dangerous "treatments" such as drinking bleach or pure alcohol.
Conspiracy theories have included claims that the virus was deliberately created to reduce population growth, or that its spread is somehow linked to 5G communications infrastructure.
Matt Brittin, head of Google Europe, said the company was committed to working with the commission and national governments "to find new and creative ways to continue the fight against disinformation".
A Facebook spokesperson said the social network had expanded its fact-checking work in Europe to 27 countries since the outbreak began, adding warning labels to about 50 million pieces of content around the world.
Vaccines 'Next Battleground'
The EU report said a new approach was needed because of the wide range of dangerous or misleading material appearing online.
Much of it is not illegal but still harmful, and also includes hate speech, consumer scams and influence-peddling operations by foreign powers.
The 17-page report accuses Moscow and Beijing of "seeking to undermine democratic debate and exacerbate social polarisation, and improve their own image in the COVID-19 context."
As parts of the world begin to ease their virus lockdowns as the first wave of the pandemic slows, Jourova warned the torrent of disinformation would not let up.
"Vaccination seems to be the next battleground," she said, referring to a suspect report out of Germany about the willingness to vaccinate.