A European Union regulator slapped Chinese-owned social media platform TikTok with a 345-million-euro fine on Friday over flaws in the video platform's personal data processing for under 18 users.

Ireland's Data Protection Commission imposed the fine and required TikTok to comply with the EU's strict General Data Protection Regulations.

The regulator highlighted in its ruling Friday how children signing up had TikTok accounts set to public by default, meaning anyone could view or comment on their content.

It also criticized TikTok's "family pairing" mode, which is designed to link parents' accounts to those of their teenage offspring, but the DPC found the company did not verify parent or guardian status.

TikTok, a division of Chinese tech giant ByteDance, is extremely popular among young people with 150 million users in the United States and 134 million in the EU.

It disagrees with the verdict and was "evaluating" how to proceed.

"The DPC's criticisms are focused on features and settings that were in place three years ago, and that we made changes to well before the investigation even began, such as setting all under 16 accounts to private by default," a TikTok spokesperson told Agence France-Presse.

The platform insists that it closely monitors the age of its users and takes action when needed.

TikTok says it deleted almost 17 million accounts worldwide in the first three month of this year due to suspicions that they belonged to people under 13 years old.

GDPR came into force in 2018 and was the EU's toughest and most famous law on tech, ensuring citizens give consent to the ways in which their data is used.                      WITH AFP