By David Shepardson

WASHINGTON (Reuters) -Two tech groups on Monday backed TikTok in its lawsuit seeking to block enforcement of a Montana state ban on use of the short video sharing app before it takes effect on Jan. 1.

NetChoice, a national trade association that includes major tech platforms, and Chamber of Progress, a tech-industry coalition, said in a joint court filing that "Montana's effort to cut Montanans off from the global network of TikTok users ignores and undermines the structure, design, and purpose of the internet."

TikTok, which is owned by Chinese tech giant ByteDance, filed a suit in May seeking to block the first-of-its-kind U.S. state ban, arguing it violates the First Amendment free speech rights of the company and users.

A hearing on TikTok's request for a preliminary injunction is set for Oct. 12.

TikTok, which is used by more than 150 million Americans, has faced growing calls from U.S. lawmakers for a nationwide ban over concerns about possible Chinese government influence.

TikTok says it "has not shared, and would not share, U.S. user data with the Chinese government, and has taken substantial measures to protect the privacy and security of TikTok users."

The tech groups said "if allowed to take effect, the ban will usher in a balkanized internet where information

available to users becomes regionally divided based on local politicians’ whims or preferences." They added "the internet,

as a whole, will become fragmented and its value to humanity diminished."

Montana could impose fines of $10,000 for each violation by TikTok. The law does not impose penalties on individual TikTok users.

TikTok estimates 380,000 people in Montana use the video service, or more than a third of the state's 1.1 million people.

Former President Donald Trump in 2020 sought to bar new downloads of TikTok but a series of court decisions blocked the ban from taking effect.

(Reporting by David Shepardson; Editing by Muralikumar Anantharaman and Edwina Gibbs)