TikTok has become another battleground showcasing China-US tensions, with President Joe Biden's administration accusing the app of allowing Beijing to collect data and spy on users -- claims denied by China and TikTok's owner ByteDance.

The United States passed a law last year forcing ByteDance to either sell the platform or shut it down by January 19.

With that deadline looming, Xiaohongshu -- a lifestyle-focussed Instagram-meets-Pinterest alternative -- surged to the top of the Apple App Store downloads on Monday.

The hashtag "tiktokrefugee" had more than 100 million views by Tuesday evening.

"They are trying to ban TikTok because they said China is stealing information. They don't ban any American company from stealing our information," user penguinpepperpia, who has more than 264,000 TikTok followers, told AFP.

The content creator downloaded Xiaohongshu rather than return to US platforms such as Meta's Instagram and Facebook, which they characterised as apps for "older people" that also "steal your personal information and sell it to other companies".

"That is why many Americans don't care anymore and we would rather let China have our information," said the user.

Other "refugees" shared similar sentiments.

New Xiaohongshu user Adham said in a video posted on Monday: "I know our government is a little bit racist, but Chinese people, I love you guys. I don't care if you take my data. Take it."

- 'Deliciously ironical' -

The phenomenon showed how "foolish" the TikTok ban was, Milton Mueller, a professor at the Georgia Tech School of Public Policy who filed a brief in opposition of the ban to the US Supreme Court, told AFP.

"It is deliciously ironical that the threat of a ban is backfiring so quickly, even before it is put into place," he said.

"It does seem as if the TikTok ban is pushing users towards other apps that have a much less clear division between the Chinese Communist Party and the app itself," Duke University's Robyn Caplan said.

Neither Xiaohongshu or ByteDance commented on the situation when asked.

What the phenomenon showed was that the Biden administration's strategy towards Chinese technology of "small yard, high fence" was not effective, said the London School of Economic's Meng Bingchun.

"The yard keeps getting bigger, and the fence is leaky," Meng said.

"Worse still, in this case, those living within the fence can be migratory in the digital space."

- Short-term reaction? -

Until Monday, Xiaohongshu -- or RedNote in English -- was popular primarily among Chinese-speaking users.

It boasted 300 million monthly active users at the end of 2023.

Unlike TikTok's sister app Douyin or the micro-blogging site Weibo, Xiaohongshu skews heavily towards lifestyle content.

It is seen as facing relatively less censorship than other platforms: users can be found posting LGBTQ content and discussing the merits of women remaining single, topics often considered sensitive in China.

For "native" Xiaohongshu users on Monday, the influx of Americans was a head-scratcher but also provided an unexpected opportunity for cultural exchange.

Some even asked for help with English homework.

In public group chats on the platform, new users asked for translations of slang terms, as well as keywords to search for content they wanted.

"It's funny and ironic that the Americans and the Chinese are meeting online under the circumstance that the US government is banning TikTok... similar to what the Chinese government has been doing for ages to American apps," 26-year-old Amanda Zhang told AFP.

The part-time pet content creator, who studies in the United States, said she was worried the US government might move to ban Xiaohongshu too if it gained enough traction.

It remains unclear what the long-term implications of the shift will be.

Xiaohongshu's main challenge to retaining these new users is translation, Caplan said.

LSE's Meng added: "My hunch is that what we are witnessing now is more of a short-term reaction than a long-term trend.

"The question now is whether there will be a critical mass of these refugees to achieve the desired network effect for the platform, and whether Xiaohongshu will respond quickly enough to harness the new users."