New Vietnamese internet rules requiring Facebook and TikTok to verify user identities and hand over data to authorities came into force on Wednesday, in what critics say is the latest attack on freedom of expression.

Under "Decree 147," all tech giants operating in Vietnam must verify users' accounts via their phone numbers or Vietnamese identification numbers and store that information alongside their full name and date of birth.

They must provide that data to authorities on request and remove any content the government regards as "illegal" within 24 hours.