BEIJING - More than 1,500 tip-offs have been received since Chinese authorities launched a campaign against online extortion and paid post deletions on Jan 21.

The information has been submitted via emails or phone calls. Of them, 492 useful tip-offs have been transferred to law enforcement departments, according to the illegal and harmful information reporting center.

Zhang Chenggang, head of the center, said the public has been active in reporting illegal activities and the staff of the center has been working around the clock to receive information.

Reported cases included websites that collect or publish negative information on enterprises and individuals in order to ask for money to delete such posts, websites that indirectly collect fees for post deletions as advertising fees or sponsorship; websites and blogs that allegedly extort enterprises or individuals in the name of rights defense, supervision or exposure.

There were also fake press or industry websites, online PR companies and QQ group accounts or personal accounts that engage in post deletion, according to the center.

The illegal websites or personal accounts charged enterprises or individuals 500 to 3,000 yuan ($80 to 480) for deleting posts.

The campaign, organized by the the cyberspace administration, the State Administration of Press, Publication, Radio, Film and Television and the ministries of public security, industry and information technology, includes a six-month crackdown on illegal websites and online companies, as well as a three-month purge targeting Internet regulators who abused their power to make profits.

Peng Bo, the cyberspace administration's deputy head, said online extortion and paid post deletions break the law, damage the orderly flow of information on the Internet and disrupt market order. They harm the image of regulators and media, he said.

The administration closed more than 2,200 illegal websites, shut down more than 300 illegal online sections and closed more than 20 million illegal online forum, blog, Wechat and QQ accounts in 2014.