BEIJING, April 30 -- China's press regulator announced Thursday that it has revoked publishing licenses of a business news website and a weekly newspaper that were caught blackmailing.

The website of the 21st Century Business Herald newspaper and the weekly publication Money Week were penalized after they were found to have forced clients to sign advertisement and service contracts by threatening to publish negative news about them, said the State Administration of Press, Publication, Radio, Film and Television (SAPPRFT) in a statement.

The website and weekly, along with the 21st Century Business Herald newspaper, were also found to have irregular management practices, the statement said.

The 21st Century Business Herald was ordered to conduct internal inspections and restructuring of its management board, it said.

The website and both newspapers are affiliated with 21st Century Media Ltd.

About 30 suspects involved in the cases, including Shen Hao, former president of 21st Century Media Ltd., were arrested and put under criminal investigation for forced transactions, blackmail, breach of duty and accepting bribes. In February, prosecutors started to review their cases and prepare for prosecution.

"Media involved in blackmail have had a vile social impact, seriously harmed public interests, undermined market order and marred the credibility and image of journalists," the SAPPRFT said.

The SAPPRFT statement warned all media organizations to learn from the incident and step up their internal regulation of news reporting.

Press regulators said they will continue fighting misconduct, and those who indulge in wrongdoing, harbor offenders and neglect their duties will face investigation and punishment.