Chinese police have arrested six people and shut 16 websites after rumours spread that military vehicles were on the streets of Beijing.
The web posts were picked up last week by media outlets around the world, amid uncertainty caused by the ousting of top political leader Bo Xilai. Mr Bo was removed from his post amid allegations that his police chief and former ally had tried to seek asylum at a US consulate.
The State Internet Information Office said the rumours had a "very bad influence on the public".
Two popular microblogs have temporarily stopped users from posting comments, the BBC reports.
The two sites are still letting people post to their own sites. But they said commenting on other people's posts would be disabled until 3 April, so they "could act to stop the spread of rumours".
A spokesperson for the SIIO told state news agency Xinhua earlier that the two websites had been "criticised and punished accordingly".
He added that a number of other people had been "admonished or educated".