The Japanese operator of the popular video-sharing app TikTok was discovered to have paid influencers to post videos on Twitter without informing the audience about the sponsored content, a practice that may have violated industry rules against stealth marketing.

The undisclosed payments to influencers were "for the purpose of spreading TikTok content," a manager at the Tokyo offices of TikTok owner ByteDance told Nikkei on Monday. This arrangement started about two years ago and stopped at the end of 2021, the unit said.

A manager from ByteDance's Japanese arm would offer contracts to influencers that come with compensation. The manager would then identify TikTok videos to be shared on Twitter. This was part of a promotional strategy pushed forward by the Tokyo offices.

Stealth marketing campaigns present themselves as word-of-mouth buzz without disclosing the sponsorship by an advertiser. There are no Japanese laws banning stealth marketing, but guidelines from an industry group forbid the practice because it misleads consumers.

Chinese startup ByteDance's Japanese subsidiary said it regrets giving consumers the wrong impression.

TikTok gained a large youthful following in Japan after launching services there in 2017. Last year saw a boom in so-called "TikTok sales" of products featured in videos on the platform.