New Delhi, Feb. 9 -- The European Union on Friday accused TikTok of breaching the bloc's digital rules with "addictive design" features that lead to compulsive use by children, in preliminary charges that strike at the heart of the popular video sharing app's operating model.

EU regulators said their two-year investigation found that TikTok hasn't done enough to assess how features such as autoplay and infinite scroll could harm the physical and mental health of users, including minors and "vulnerable adults."

The European Commission said it believes TikTok should change the "basic design" of its service. The commission is the EU's executive arm and enforcer of the 27-nation bloc's Digital Services Act, a sweeping rulebook that requires...