China's state media say the government has closed down 16 websites, arrested six people, and punished two social media sites for circulating rumors about a coup.
Xinhua said late Friday the crackdown came after a surge in online rumors about a coup following the dismissal of a popular politician - Bo Xilai - leader of the city of Chongqing.
Analysts say the clampdown underscores China's anxieties over a public that is wired to the Internet and eager to discuss political events despite censorship and threats of punishment.
Some information for this report was provided by AP and AFP.