German sportswear giant Adidas has launched an investigation into alleged large-scale bribery in China after senior employees were accused of embezzling millions of dollars, the Financial Times reported Sunday.

A letter, allegedly written by "employees of Adidas China", accused several Chinese employees by name, the paper reported.

Those accused included one of the company's executives involved with Adidas' marketing budget in China, which it said stood at 250 million euros ($268 million) a year.

Another Adidas China manager is said to have received "millions in cash from suppliers, and physical items such as real estate", according to the FT.

Adidas could not be reached immediately for comment.

The letter, which was posted this month on the Chinese social media platform Xiaohongshu, was no longer visible on the website on Sunday, but a purported copy, the authenticity of which AFP was unable to verify, was posted on several accounts.

Adidas had received a letter on 7 June alerting it to "potential compliance violations in China" and was "intensively investigating" the matter, the FT said.

Company insiders quoted by the paper said the letter did not provide evidence for the allegations but appeared well-informed about confidential internal issues.