TikTok could face a €30m fine for failing to protect children's privacy when they use the platform.
The UK's Information Commissioner's Office (ICO) found that the video-sharing platform may have processed the data of under-13s without proper consent. The watchdog said the breach took place over two years - until July 2020 - but that it had yet to draw a full conclusion.
TikTok says it disputes the findings, noting they are "provisional".
The ICO has put TikTok Inc and TikTok Information Technologies UK Limited on notice "for the purpose of investigation" with a legal document that precedes a potential fine.
The notice sets out the ICO's provisional view that TikTok breached UK data protection law between May 2018 and July 2020.
The ICO's investigation found that the social platform may have: processed the data of children under the age of 13 without proper parental consent, failed to provide appropriate information to its users in a concise, transparent and easily understandable way, has processed data of special categories, without a legal basis to do so.
According to Ofcom, 44 percent of eight to 12-year-olds in the UK use TikTok, despite its policies banning children under 13 from the platform.