The suspects used social-networking services to spread rumours or had forwarded rumours published on foreign websites, the state-run Xinhua News Agency reported on Saturday. The rumours included predictions of an earthquake in Beijing and gunshots being heard in the west of the city, the news agency said.
China has been clamping down on the use of the internet, instant messaging and social media since Xi Jinping became president in 2012. The government issued a law in September dictating that authorities could jail Web users for up to three years if they post comments deemed defamatory.
Police detained a man in eastern Jiangsu province for spreading rumours on the "Moments" function of the WeChat application related to the killing of terrorists, Xinhua reported on Friday.
The four suspects may face defamation charges, which under Chinese law are brought against those whose posts are deemed to be rumours and viewed by more than 5,000 users and retweeted more than 500 times, according to the Xinhua report.
Police have also detained or warned 81 others for similar but slighter offences, Xinhua reported. Sixteen websites have also been punished for “weak safety management", the report said, without giving further details.