China launched an anti-pornography campaign in April as part of wider efforts to "clean up" the Internet. The move has coincided with a crackdown on online freedom of expression, which has intensified since President Xi Jinping came to power early last year.
Xinhua said mobile game platforms run by Tencent, which runs one of the most popular mobile messaging apps in China, search engine giant Baidu and another nine companies were alleged to be involved in pornography, gambling and violence.
The report cited a statement from the culture ministry as saying that some products had challenged "accepted moral values".
Spokespeople for Tencent and Baidu did not answer calls to their mobile phones late on Tuesday in China.
Liu Qiang, a deputy director in the market department of the ministry, said the fine amounts would be published later.
"We hope that major companies can shoulder their due, social responsibilities and offer healthy, quality, cultural products," Xinhua cited Liu as saying.
The ministry also discovered comic and animated products that contained "bloody, terror and violent content" on 21 websites run by companies such as China Telecom and Tencent, Xinhua said.
In August, Chinese authorities warned Baidu to clean up its content after pornographic files were found on its online storage service.
In May, Internet firm Sina Corp. was fined 5.1 million yuan by Beijing authorities for allowing "unhealthy and indecent content" on its online reading channel and on its main website.
© Thomson Reuters 2014
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