China's gaming companies should step up their social responsibility by paying more taxes, a state-owned media outlet said Thursday, stoking concerns that a regulatory crackdown may be looming.

Securities Times, a newspaper affiliated with Communist Party mouthpiece People's Daily, said that, after years of enjoying government subsidies and tax cuts, the gaming sector should brace for taxation that aligns with that of other industries.

"When these software industries have developed and gained comparative advantages, there is no need for the government to continue to provide industrial support," the article said.

Shares of Tencent Holdings Ltd., China's largest videogame company, fell close to 5% Thursday afternoon in Hong Kong, while rivals NetEase Inc. and Bilibili Inc. also dropped by similar amounts.

All three stocks are on track to post weekly losses. Tencent is down about 9% so far this week, while Bilibili has lost 7% and NetEase has shed roughly 12%.

Thursday's article comes two days after another state media outlet described online gaming as "opium for the mind," and as officials and media urge gaming companies to implement stricter measures to prevent minors from becoming addicted to games.

The criticisms have sparked concern among investors already unnerved by Beijing's months-long regulatory crackdown on the technology sector.

The calls for tougher regulation follow the implementation of the country's revised minor-protection law in June. The revision includes a chapter on cyberspace protection requiring parents, schools and social institutions to jointly take action to prevent internet addiction among minors. Chinese President Xi Jinping had in March cited gaming addiction as a concern, saying that it could be a bad influence on minors, according to a copy of a speech he made at a meeting that was published by People's Daily.

Chinese regulators have been seeking to regulate the country's fast-growing gaming industry and limit the amount of time minors spend on games since 2017, and many companies already have systems in place to curb gaming addictions.

Tencent on Tuesday said it will implement more protections for minors and called for an industry-wide ban on gaming for children under 12.

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