Online media basing news reports on contents made on social media must verify them before publication, China's Internet regulator said on Sunday.
News websites must accredit these sources, and they are banned from fabricating stories or distorting facts, according to a notice issued by the Cyberspace Administration of China (CAC).
The CAC has punished some major websites which have fabricated stories this year, including sina.com, ifeng.com, 163.com and the site run by one of the country's biggest Internet companies, Tencent.
In one notorious case, a journalist from the respected Caijing Magazine wrote a story in February based on fabricated online content describing a village in northeast China where villagers do not respect the elderly and women are promiscuous. The story went viral.