Italy's competition watchdog said Tuesday it had opened an investigation into video app TikTok for failing to enforce its own rules on removing "dangerous content" related to suicide and self-harm.

The Italian Competition Authority said its probe, which targets Irish company TikTok Technology Limited, a subsidiary of Chinese-owned TikTok, was sparked by videos of young people "adopting self-harming behaviour", including the "French scar challenge".

In the challenge, children pinch their cheeks violently to create bruising, a phenomenon explained by numerous tutorials on TikTok that has caused concern in the education and health sectors.

The watchdog said it had carried out an inspection of the Italian headquarters of TikTok on Tuesday with the help of financial police.

"The guidelines of the companies who own the platform, which envision the removal of dangerous content that instigate suicide, self-harm and unhealthy nutrition, are not applied," said the watchdog in a statement.

It accused the platform of failing to set up adequate monitoring systems, especially given the many "particularly vulnerable" minors who used it.

In a statement, TikTok said it employed more than 40,000 "safety professionals" and said it does not allow content "showing or promoting" the activities cited by the watchdog.

"We take extra care to protect teenagers in particular," it said.

Western authorities have been taking an increasingly firm approach to TikTok, owned by Chinese parent company ByteDance, over fears that user data could be used or abused by Chinese officials.

Following in the footsteps of the United States and the European Union, the UK on Thursday banned the application on government devices.

The app, which boasts more than one billion active users, is regularly accused of spreading disinformation, putting users in danger with hazardous "challenge" videos, and allowing pornography, even though it is supposed to prohibit nudity.

Several children have also reportedly died while trying to replicate the so-called blackout challenge, which involves users holding their breath until they pass out.