Cell phone giant China Mobile has frozen contracts with its mobile Internet partners in order to stem criticism that pornography was being sold through its network.

The move by the mobile phone company means it will not collect fees for its online partners, rendering paid services unavailable.

China Mobile's music business unit has also temporarily ended cooperation with 256 Internet retailers.

"All service providers that have commissioned us to collect fees for their businesses online are required to guarantee that their services are free from porn and are not commercially related to any pornographic websites for mobile phones," Wang Jianzhou, chief executive of China Mobile, said in a press release Monday.

Three major wireless carriers in China, including China Mobile - all State-owned - are coming under mounting pressure to eradicate access to pornography through mobile phones.

More than a dozen Chinese ministry-level government departments have launched a joint crackdown on pornography on mobile phones in recent months.

Mobile carriers were put under their scrutiny after complaints that websites available only to cell phone users were skirting government controls and providing easy access to pornography.

"The telecom operators collect fees from mobile services and these operators take most of the profits generated by porn content on the mobile sites," Wang Song, an official with the multi-sector Office Against Pornographic and Illegal Publications, told Xinhua News Agency.

"So the operators should take responsibility (for cutting the links)."

However, most Internet regulatory bodies have no effective means of monitoring mobile sites, and the manual checks currently employed are slow, Wang said.

China's three major wireless carriers, China Mobile, China Telecom and China Unicom, offer online services to about 192 million mobile phone users, more than half of the total number of Internet users in the country.

The China Internet Illegal Information Reporting Center said on Nov 24 that it is receiving a growing number of tip-offs about mobile pornography sites.

On Nov 16, the Office Against Pornographic and Illegal Publications announced a crackdown on the creation and distribution of lewd material, which focused on the cities of Shanghai, Beijing, and Guangzhou, as well as Zhejiang province, where many of the sites involved are registered.

It ordered local authorities to "clean up" such sites and shut down those with "serious violations".

The office said the campaign was launched due to concerns over minors having access to pornography.

In a survey of 235 middle school students conducted by the office in Shanxi province, 74 percent had mobile phones and 60 percent had logged on to mobile sites.

Of the 199 senior high school student respondents, 83 percent knew that some sites had pornographic content.

"Children and adults alike can easily log on to such sites," said Li Qiang, a doctor with the Chinese Academy of Sciences, who has initiated several reports against mobile Internet service providers over the issue.

Xinhua contributed to the story