TikTok received more bad news on Wednesday after Montana Governor Greg Gianforte (R) signed into law a bill banning the popular app from January 1, 2024.

While more than half of U.S. states have already issued TikTok bans on government-issued devices, Montana’s action against the Chinese-owned app is significant as it’s the first state to impose a total ban on the app.

“Today, Montana takes the most decisive action of any state to protect Montanans’ private data and sensitive personal information from being harvested by the Chinese Communist Party,” Governor Gianforte said in a release.

The governor also announced the move in a tweet, saying: “To protect Montanans’ personal and private data from the Chinese Communist Party, I have banned TikTok in Montana.”

To protect Montanans’ personal and private data from the Chinese Communist Party, I have banned TikTok in Montana.

— Governor Greg Gianforte (@GovGianforte) May 17, 2023

U.S. authorities have long expressed concerns about TikTok, fearing that its Beijing-based owner, ByteDance, may be open to interference from the Chinese government and therefore presents a national security risk. Some believe the Chinese authorities have access to TikTok user data belonging to U.S. citizens, and can even influence the app’s algorithm to serve up pro-China content. TikTok has always strongly rejected such accusations.

Responding to the latest action, TikTok said in a release that the Montana bill “infringes on the First Amendment rights of the people of Montana by unlawfully banning TikTok,” adding that the company plans to “defend the rights of our users inside and outside of Montana.”

Montana’s new law will ban downloads of TikTok within its state borders and says app stores or TikTok itself will face fines if they facilitate downloads there. Individuals using TikTok will not face any kind of penalty.

Montana’s ability to successfully enforce the new law remains to be seen, but it could certainly turn out to be a significant step if other states follow its example in the coming months. Such action could rapidly lead to a nationwide ban prompting Apple and Google to remove TikTok from their U.S. app stores.