Italy's data protection watchdog has ordered TikTok to block access to users whose age cannot be confirmed.
The ban comes just days after the death of a young girl in Palermo, who had been taking part in an online "challenge" that has been viral on the platform.
"The Italian Data Protection Authority (GPDP) has ordered Tik Tok to immediately block the use of user data for which the age of the user has not been ascertained with certainty," it said in a statement.
"The authority decided to intervene as a matter of urgency following the terrible case of the 10-year-old girl from Palermo."
The Chinese-owned app has been prohibited from processing user data that is not "in compliance with the provisions related to the age requirement".
The temporary ban will last until 15 February as the authority continues to assess data privacy regulations. The GPDP also stated that they had informed Irish data protection authorities "given that recently TikTok has announced that it has set its main establishment in Ireland".
The President of Italy's Commission for childhood and adolescence, Licia Ronzulli, described the ban as "right and timely" on Twitter.
"The safety of minors must be protected at all costs and we cannot, as happened in Palermo, allow a social network to be an accomplice in a suicide".
Tiktok had already been accused of data privacy violations by the GPDP in December over the "lack of attention to the protection of minors".
The social network had also been accused of weak policies, which allowed users under the age of 13 to circumvent age-restricted rules.
The public prosecutor's office in Palermo indicated that it has opened an investigation into TikTok for "incitement to suicide" after the 10-year-old's death by asphyxiation, which provoked strong reactions across Italy.
"The safety of the TikTok community is our top priority," the platform said in a statement, adding, "we are at the disposal of the competent authorities to collaborate in their investigation".
Pressure also building on other platforms
Italy has also asked Facebook and Instagram for clarification on how easy young people can access other social networks in the wake of the girl's death in Palermo.
"In recent days, some press articles reported the news that the minor would have several profiles open on the two social networks," the authority added in a later statement.
"We therefore asked Facebook ... to provide a series of information, starting from how many and which profiles the minor had and, if confirmed, how it was possible for a 10-year-old minor to subscribe to the two platforms."
The watchdog said that their priority was to establish precisely how users register for Facebook and Instagram and whether the relevant checks are carried out to support the minimum age registration.
Facebook, which also owns Instagram, has 15 days to respond to Italy.
According to the Authority, investigations would also be extended to other social networks "in particular with regard to the methods of access to the platforms by minors."