Chinese police have arrested more than 15,000 people to date for cyber crimes, including hacking and fraud, while activists said the crackdown is also linked to the ruling Chinese Communist Party's ongoing war on online public opinion.
"More than 15,000 criminal suspects were detained in investigations of more than 7,400 Internet crimes by police departments and agencies," the country's ministry of public security said in a statement on its website.
Those detained were suspected of "harming national security online" or "infringing the legitimate rights and interests of the general public," it said.
It listed hacking attacks, cyber fraud and the promotion of online gambling among the crimes under investigation.
In a case in the eastern province of Jiangsu, seven people were arrested after hackers took control of a company website, filling the pages with online gambling content, the ministry said.
The suspects were later found to have hacked into more than 2,000 websites.
But China is also deleting content that the government deems offensive and "harmful," including pornography and gambling, but also posts by citizens about current events that are considered "rumor-mongering" because they offer an alternative view of events.
Pan Lu, deputy director of the nascent China Human Rights Monitor group, said the crackdown on so-called cyber crime is linked to the nationwide "stability maintenance" system run by police.
"The police ... are the main force behind stability maintenance, because China is a police state," Pan said. "Their aim is to maintain their time control on public opinion, to support the party and state-run media and to ensure that the lies put out by the system can continue."
"They can't tolerate dissent, and they are sowing terror online, to the extent that ... citizens like us aren't able to make their voices heard," she said.
"They don't want to hear any critical or interfering voices online when they are dealing with thorny crises."
Clamp down on reporting
In recent days, China has clamped down on reporting of last week's devastating Tianjin chemical warehouse explosions, ordering state-run media to stick to officially approved news stories, deleting tweets, and shuttering social media accounts deemed to be "spreading rumors" about the Tianjin explosions.
Veteran Hebei-based reporter Zhu Xinxin said the definition of what constitutes an "Internet crime" remains very wide in China.
"For example, if you commit financial fraud using the Internet, it's understandable that this would be considered a cyber crime," Zhu said.
"Of course, there are political implications with these so-called cyber crimes, and the Chinese Communist Party uses Internet crime as a pretext to purge freedom of speech online," he said.
"[This could include] expressions of dissatisfaction with the government or current issues, speaking the truth about actual events, disasters or emergencies, or exposing official corruption," Zhu added.
"All of these things can lead to an arrest in the name of cyber crime, which constitutes a violation of human rights, and an attack of freedom of speech."
Earlier this month, Beijing announced it would further tighten its grip on the nation's 650 million netizens with the stationing of specialist police officers in major Internet companies.
Hacker attacks, "violent terrorist information," fraud and data theft, pornography and gambling are mushrooming online, posing a serious threat to social stability and national security, and police should "play a dominant role" in the management of online security, according to the ministry.
Meanwhile, a draft cybersecurity law published by the National People's Congress (NPC) looks set to formalize and extend government controls over the Chinese Internet.
The draft law aims to "ensure network security, [and] safeguard the sovereignty of cyberspace and national security," according to the NPC’s official website, and will ensure Chinese Internet users aren’t allowed to "disturb the social order, [and] harm the public interest.
Rights groups say this could lead to further tightening of the existing set of blocks, filters and human censorship known collectively as the Great Firewall, while officials say they are also setting out to protect Chinese infrastructure from cyberattacks and the privacy of citizens’ data.
Reported by Xin Lin for RFA's Mandarin Service. Translated and written in English by Luisetta Mudie.