Facebook whistleblower Frances Haugen has said the EU could set the global "gold standard" on curbing the power of big tech, lending a boost to a European push for new laws against US giants.
The former Facebook engineer leaked a trove of internal documents that have sparked weeks of criticism of the social media giant and a major push worldwide to get tough on big tech.
Ms Haugen brought her arguments to key lawmakers in Brussels after giving testimony in Washington and London and ahead of a stop in Paris.
The EU is currently pushing through new laws that could force the world's biggest tech firms to rethink the way they do business.
Ms Haugen endorsed the plans, especially the Digital Services Act which would create much stricter oversight of harmful and illegal content on platforms like Facebook.
"I am grateful that the European Union is taking this very seriously. The Digital Services Act that is now before this parliament has the potential to be a global gold standard," she told MEPs at a hearing in Brussels.
Describing it as having "huge potential", she said EU rules "can inspire other countries, including my own."
In her testimony, Ms Haugen said Facebook chooses profit over curtailing toxic content and insisted that the company could not be trusted to change its ways.
"Facebook cannot remain the judge, jury, prosecutor and witness" of its widespread malpractice, Ms Haugen told MEPs during more than two hours of testimony.
"The decisions made by Facebook's leadership are a big problem. For children, for public safety and for democracy," Ms Haugen said.
The EU laws also include the Digital Markets Act, which creates a strict list of 'Do's and Don'ts' for big tech that could include a potential ban on buying certain companies.
Both laws are currently inching their way through the European Parliament and meetings of EU national governments, with hopes that they can be finalised when France
takes over the presidency of the bloc, between January 1 and June 30 next year.
Backers of the laws want Ms Haugen's visit to jump-start a process that has become bogged down in details and a lobbying frenzy by the tech industry.
Increased lobbying efforts by large tech firms "are in vain", said EU commissioner Thierry Breton after meeting Ms Haugen.
"We need the DSA/DMA package adopted in the first half of 2022. We also need to remain extremely ambitious in our response," Mr Breton said.
The toughest wrangling by lawmakers has been over the fate of targeted ads, as well as which tech companies would fall under the laws' toughest rules.
Facebook has said Ms Haugen's allegations distort reality and described her as a mid-level engineer with limited access to important decisions.
At the heart of her claim "is a false premise", said Monika Bickert, vice president of content policy at Meta, Facebook's parent company.
"Yes, we're a business and we make profit, but the idea that we do so at the expense of people's safety or well-being misunderstands where our own commercial interests lie," she said in a blog entry.
Slovenia, which currently holds the EU's rotating presidency, is hoping the bloc's 27 member states will clinch a common position on both laws at a meeting on November 25.
The European Parliament would like its texts voted by January at the latest. Negotiators would then attempt to blend both versions in the six months of France's presidency of the EU.
German MEP Anna Cavazzini told AFP that Ms Haugen's testimony would allow parliament to make "informed decisions".
Facebook is "still a black box" whose inner workings are shielded from scrutiny, she said.