Others targeted by the online police included a prominent real estate magnate and a couple of well-known rights lawyers.
Political expression in the public sphere is often viewed as risky in China, where the authoritarian government frequently harasses and even jails dissidents for pro-democracy calls.
Also joining the chorus were 18 Chinese academics who signed an open letter calling for the dismissal of Tuo Zhen, a provincial propaganda minister blamed for the censorship. The scholars included legal professors, liberal economists, historians and writers.
Six weeks ago, China installed a new generation of Communist Party leaders for the next five years, with current Vice President Xi Jinping at the helm. Some of Xi's announcements for a trimmed-down style of leadership, with reduced waste and fewer unnecessary meetings, have raised hopes in some quarters that he might favor deeper reforms in the political system to mollify a public long frustrated by local corruption.
The Guangdong provincial propaganda department did not immediately respond to a faxed list of questions. But the Communist Party-run Global Times newspaper said in an editorial that no Chinese media outlet should fool itself into thinking that it could occupy a "political special zone" in which it is free from government control.
The U.S. State Department said Monday that media censorship is incompatible with China's aspirations to build a modern information-based economy and society. Spokeswoman Victoria Nuland said it was interesting that Chinese are now strongly taking up their right to freedom of speech.
"We hope the government is taking notice," she told a news briefing in Washington.
Chinese Foreign Ministry spokesman Hong Lei told reporters in a regular briefing that Beijing is opposed to any country or individual interfering in China's internal affairs.
Associated Press writers Didi Tang in Beijing and Matthew Pennington in Washington and researcher Flora Ji in Beijing contributed to this report.