Photo: Reuters / Paul Hanna

Authorities in China have shut down dating apps associated with 21 companies, arresting more than 600 people suspected of involvement in creating fake bot accounts, according to Chinese website Xinkuai.

Tens of thousands of people are believed to have been conned out of some US$154 million, targeted in some cases by automatically generated messages, the BBC said, citing the police report.

Suspects allegedly created fake “sexy girl” accounts, writing computer programs to generate greeting messages and compliments sent to new users.

“They solicited gifts and posted other messages to lure the user into spending money, and thus illegally generating profit,” the police report was quoted as saying.

Groups involved were operating across thirteen provinces, including Shanghai, Beijing, Hangzhou and Shenzhen.

One app, identified as Moucheng, defrauded more than US$52 million from users, according to the Xinkuai article.

The scandal comes amid an ongoing crackdown on dating apps in the country, targeting alleged marriage scams. A set of guidelines published by authorities in September requires websites to take additional measures to vet users’ identities.

The rules are reportedly designed to regulate China’s “marriage market,” as the South China Morning Post put it, in conjunction with the Communist Youth League’s efforts to expand state-sanctioned matchmaking channels.