China has described a potential TikTok ban in the United States as "an act of bullying" that would ultimately backfire on America, just hours before the House of Representatives is set to vote on legislation that would force the popular short video app's Chinese owner ByteDance to sell the company or face being barred in the US.

"Even though the US has not found evidence on how TikTok endangers its national security, it has never stopped going after TikTok," Wang Wenbin, a spokesperson for China's foreign ministry, told CNN Wednesday at a news conference in Beijing. "This kind of bullying behaviour that cannot win in fair competition disrupts companies' normal business activity, damages the confidence of international investors in the investment environment, and damages the normal international economic and trade order."

The House vote, which is expected to pass overwhelmingly with bipartisan support, would mark the biggest threat yet to TikTok, which has surged to huge popularity across the world while raising fears among governments and security officials over its Chinese ownership and potential subservience to the Communist Party in Beijing.

US officials and lawmakers have long voiced concerns that the Chinese government could compel ByteDance to hand over data collected from US users or use the app as a tool to spread propaganda, misinformation, or influence Americans. However, cybersecurity experts say that the national security concerns surrounding TikTok remain a hypothetical - albeit troubling - scenario, with US officials not publicly presenting evidence that the Chinese government has accessed the user data of US TikTok users.

Wisconsin Republican Rep. Mike Gallagher, who chairs a House select committee on China, rejected characterizations of the bill as a TikTok ban, stating, "It's not a ban. It puts the choice squarely in the hands of TikTok to sever their relationship with the Chinese Communist Party. As long as ByteDance no longer owns the company, TikTok can continue to survive ... the basic ownership structure has to change."

China has previously said it would "firmly oppose" any forced sale of TikTok, with a spokesperson for China's commerce ministry stating in March last year that "the sale or divestiture of TikTok involves technology export, and administrative licensing procedures must be performed in accordance with Chinese laws and regulations."

On Chinese social media site Weibo, TikTok was ranked among the top trending topics on Wednesday, with the hashtag "Tiktok starts to fight back" drawing 80 million views. Many users voiced support for the app and its efforts to contest the bill, which include a full-screen notification encouraging users to call their representatives, while some accused the US of being hypocritical.

The state-run Global Times, a nationalist tabloid, has also sprung to TikTok's defense, accusing the US of "openly trying to rob TikTok" in an editorial last week and stating that "the image of free speech and rule of law in the US is in tatters, and the latest bill is simply further evidence of this."

TikTok CEO Shou Zi Chew is currently in Washington, trying to shore up support to stop the bill. In a letter to the bill's co-sponsors seen by AFP, Michael Beckerman, TikTok's vice president for public policy, wrote, "This latest legislation being rushed through at unprecedented speed without even the benefit of a public hearing, poses serious Constitutional concerns."

The fate of the bill is uncertain in the Senate, where key figures are against making such a drastic move against the hugely popular app that boasts over 170 million US users. However, President Joe Biden has said he will sign the bill, known officially as the "Protecting Americans from Foreign Adversary Controlled Applications Act," into law if it comes to his desk.