Chinese authorities shut 16 websites and detained six people accused of spreading rumors of unusual military vehicle movements in Beijing, state media reported, after the political downfall of one of the ruling communist party’s senior leaders.

Authorities closed the websites for spreading rumors of “military vehicles entering Beijing and something wrong going on in Beijing,” Xinhua news agency said late on Friday, citing a spokesman with the State Internet Information Office (SIIO).

The spokesman said that two popular microblogging sites also had been “criticized and punished accordingly”.

The March 15 ouster of Bo Xilai as party chief of the inland city of Chongqing, who was linked to a scandal involving a senior aide, has shaken China’s Communist Party as it readies for a top leadership change later this year.

After Bo was sacked, popular microblogs, including those run by Sina Corp. and Tencent Holdings Ltd, were awash with speculation about a government coup.

Sina and Tencent shut the comment functions on their popular microblogging sites from March 31 to April 3 to “clean up rumors and other illegal information spreading” through the site, Xinhua said.

On Saturday, Sina’s Weibo users could still make posts, though other users could not respond.

Beijing-based microbloggers had previously been ordered to register their real names by mid-March or face unspecified legal consequences.

Many users fear Internet restrictions like those for Beijing and other regions are aimed at muzzling often raucous, and perhaps most significantly, anonymous, online chat in a country where the Internet offers a rare opportunity for open discussion.