The Chinese Anti-Communist Party Hackers group hijacked a primetime cable TV network on Friday, broadcasting images of tortured prisoners, anti-government slogans and footage of the Tiananmen Square protests in 1989.
For about 10 minutes, in the eastern city of Wenzhou, viewers of China Cable found the station programmes overlayed with messages denouncing the government, reports Foreign Policy.
"Damn the Chinese Communist Party's mouthpieces: China Central Television, Peoples' Daily," said one message, referring to the country's state controlled television station and main newspaper.
"A salute to people who are brave enough to strive for freedom," said one of the messages. "Do not forget June 4 (the anniversary of the Tiananmen protests). One party authoritarian rule always ends in disaster.
"Devil Communist bandits are the common enemy of mankind. Tens of millions of ghosts who were wrongly put to death are seeking revenge."
The Tiananmen protests saw thousands take to the streets in Beijing demanding an end to political repression.
China Cable, which broadcasts into 4 million households across four Chinese provinces, advised customers to take the smart card from their cable device and reset it.
One message called for the release Nobel Peace Prize winning dissident Liu Xiaobo and Wang Bingzhang, the pro-democracy activist.
Another advised viewers that they were being brainwashed, and to turn off their televisions: "Dear audience, do not watch too much television. It is all lies and self-congratulation by these ********. Television is the accomplice of the fatuous Communist party."
The local government responded that "lawbreakers" had "released malicious information".
"Please make a distinction between right and wrong and do not spread these pictures or statements," it said.
On the Chinese social networking site Weibo, posts referring to the hack were deleted by censors, and screenshots of messages were wiped.
The search term "Wenzhou TV station hacked" is currently blocked on the site due to "relevant regulations".
Initial Chinese news agency reports about the hacking were also pulled from the network.
The Anti-Communist Party Hackers' logo appeared on the side of TV screens during the attack. The group has previously claimed responsibility for hacking government websites.