TikTok, a social media phenomenon with hundreds of millions of users worldwide and around 8.5 million monthly active users in Australia, has been accused of covertly collecting views on a number of sensitive subjects among those on the platform.

The claims were made by the Department of Justice in a filing to a federal court in the US where it asked the court to reject an appeal by TikTok to overturn an April law requiring the China-based ByteDance to sell TikTok’s US assets by January 19 or face a ban.

A search tool within Lark, the web-suite system the company’s employees use to communicate, “allowed ByteDance and TikTok employees in the US and China to collect bulk user information based on the user’s content or expressions, including views on gun control, abortion, and religion,” reads one of the documents filed by the DoJ with the US Court of Appeals for the DC Circuit.

Framing it as a national security argument, the department contends that TikTok could be used to subject US users – which number around 170 million – to content manipulation, and that their sensitive information could also end up stored on servers in China.

“The serious national-security threat posed by TikTok is real,” the department said. “TikTok provides the Chinese government the means to undermine US national security in two principal ways: data collection and covert content manipulation.”

TikTok took to another social media platform, the Elon Musk-owned X, to counter that narrative. “The government has never put forth proof of its claims, including when Congress passed this unconstitutional law. Today, once again, the government is taking this unprecedented step while hiding behind secret information”, TikTok posted in response to the DoJ brief.

Australia hasn’t followed the US’ lead in attempting to ban TikTok, although the app is banned on government phones handling sensitive information. A report earlier this year noted that TikTok had supported 13,000 jobs and contributed $1.1 billion to the Australian GDP.