In a class-action lawsuit, an American college student has accused TikTok of transferring private user data to servers in China, despite TikTok owner Bytedance’s assurance that it does not store personal data there, the Daily Beast reported.

The lawsuit, filed in the US District Court for the Northern District of California last week, alleges that TikTok has “vacuumed up and transferred to servers in China vast quantities of private and personally-identifiable user data”, according to Reuters. The plaintiff, Misty Hong, alleges in the lawsuit that TikTok created an account for her without her knowledge, even though she had simply downloaded the app on her phone, but had not created an account. She alleges that TikTok collected private information about her, including biometrics from the videos that she created but never posted.

Hong further said that TikTok transferred user data to two servers in China  Tencent-owned bugly.qq.com and umeng.com  as recently as April 2019. Tranferred data included information about the user’s device and any websites the user had visited. Umeng is a part of Chinese e-commerce giant Alibaba Group.

The lawsuit also claims that source code from Chinese tech giant Baidu and Chinese advertising service Ixigen is embedded in the TikTok app. Security researchers had discovered in 2017 that Ixigen was enabling developers to install spyware on a user’s phone. There is, however, no evidence in the lawsuit of the data transfers or the existence of or Igexin source code in the app.

TikTok has seen spectacular growth since its launch outside China two and a half years ago. The app surpassed 1.5 billion downloads earlier this month, according to analytics firm SensorTower. Following India and China, the US accounted for the most downloads this year.

TikTok faces criticism on multiple fronts

US politicians have been sharply critical of the company over concerns on how it handles user data, as well as for its censorship of political content deemed sensitive by Chinese government, such as the Hong Kong protests, the Tiananmen Square protests, and most recently for suspending the account of a American woman who posted a video of her talking about treatment of Uighurs in China while giving a tutorial on eye-lash curling. TikTok has denied censorship at the behest of the Chinese government.

Bytedance now faces a national security review and declined to testify in a Senate hearing on the technology industry’s ties to China.

TikTok has faced similar concerns in India, multiple lawmakers have raised concerns over TikTok’s China connection, accusing TikTok of transferring Indians’ user data to Chinese servers; over cultural degradation, TikTok’s allegedly harmful effects on children, and even over its intermediary status.