A legal battle over First Amendment rights appeared to be brewing in Montana Thursday in response to the state’s ban on TikTok from January 1, the first of its kind in the country.

The ban, signed by Governor Greg Gianforte on Wednesday, sparked outrage from TikTok, civil liberties and digital rights groups, and angry TikTok users who called it an unconstitutional violation of free speech. Montana lawmakers and Mr. Gianforte, a Republican, say the ban is necessary to prevent Americans’ personal information from falling into the hands of the Chinese government. TikTok is owned by the Chinese company ByteDance.

Under the law, TikTok will be fined for using the app in the state, and app store providers such as Google and Apple will be fined if TikTok is made available for download in Montana.

On Thursday, neither TikTok nor leading civil liberties groups announced plans for a lawsuit. Brooke Oberwetter, a spokeswoman for TikTok, declined to comment on the possibility of a lawsuit by the company.

But Ms. Oberwetter said Wednesday, after the law was signed into law, that the ban violates Montana’s First Amendment rights and that the company will continue to “work to protect the rights of our users.” She said Thursday that the 2020 federal ban does not stand up to legal scrutiny and that Montana does not have a workable plan for a ban.

Ms. Oberwetter also pointed to statements by civic and digital groups expressing similar concerns.

Ramya Krishnan, a lawyer with the Knight First Amendment Institute at Columbia University, said the Constitution protects Americans’ right to access social media platforms of their choice. To justify the ban, Ms. Krishnan said the state of Montana would have to show that its privacy and security concerns are real and can’t be addressed in narrower ways.

“I don’t think TikTok has sued yet, but I think it will,” Ms Krishnan said. “Because this is such a dramatic and unconstitutional intrusion on Americans’ First Amendment rights, we’re certainly thinking about intervening in some way.”

NetChoice, a trade group that considers TikTok a member and has sued in the past to block state laws against tech companies, also said in a statement that the ban violates the constitution. Christa Chavez, a spokeswoman for the group, said NetChoice “does not currently plan to take legal action” to challenge the law.

Montana’s law comes after the federal government and more than two dozen states banned TikTok from government devices in recent months. Lawmakers and intelligence officials said that TikTok, due to its ownership, could put sensitive user data into the hands of the Chinese government. They also claimed that the app could be used to spread propaganda. TikTok says it has never been asked to, and has not, provided any U.S. user data to the Chinese government.

“Many have speculated that China could require ByteDance, the parent company of TikTok, to hand over American data or use TikTok to spread misinformation, but neither Montana nor the US government has provided any evidence that China is actually doing this,” she said. .Krishnan said. “This is a problem because speculative damage cannot justify a total ban on a communications platform, especially one used by hundreds of thousands of Montana residents every day.”

In addition to the potential litigation, many experts have raised questions about whether the law can actually be enforced. Internet users can use virtual private network software to hide their location. People living in Montana’s border cities can access TikTok and other mobile apps through cell towers in neighboring states.

In an email, Emily Cantrell, a spokeswoman for the state’s Attorney General, said technology exists to limit the use of apps in a specific location. The method, known as geofencing, is “already used by the gaming industry,” which is also regulated by the state’s Department of Justice, Ms. Cantrell said.

“A basic web search will show you companies that enforce geolocation,” she said. If companies do not comply with the ban, they continued, the agency will “investigate and hold offenders accountable in accordance with the law.”

The legislation places the responsibility for enforcing the ban on TikTok, Apple and Google. Under the law, TikTok can be fined $10,000 for each individual violation of the ban, and an additional $10,000 each day if the violation continues. Apple and Google would face the same fines if they allowed the app to be downloaded in the state.

While the ban was being considered by the state legislature, the trade group representing Apple and Google said the companies would not be able to restrict access to the app within the same state.

“The responsibility should lie with the app to determine where it can run, not the app store,” David Edmonson, vice president of TechNet, the trade group that represents app stores, said Thursday.

Google and Apple declined to comment.