The authorities will begin a month-long crackdown on Tencent Holdings' popular WeChat messaging application, state media reported, the latest in a series of curbs on online expression.
"Some people are using this platform to disseminate negative, harmful or illegal information to the public, seriously damaging the internet system and hurting the public interest," according to a report on state-owned China News Service, alleging the messaging service was "causing dissatisfaction among internet users".
The crackdown would focus on accounts sending information with the ability to "communicate [widely] and mobilise society", the report said.
Accounts accused of spreading rumours and ideas about violence, terrorism, cheating and sex would be targeted, said the report.
Tencent could not be immediately reached for comment.
The report went on to say that authorities would also seek to weed out domestic and foreign forces seeking to infiltrate and sabotage the nation.
Authorities closed dozens of popular internet accounts sending out social or political content in March.
Unlike popular microblogging services such as Sina Weibo, where posts can reach millions of people in minutes, WeChat allows users to communicate in small, private circles of friends, and send text and voice messages for free - which is a major part of its success.
The Communist Party renewed a campaign to regulate online discourse last year, threatening legal action against people who post rumours online which are reposted more than 500 times or viewed by more than 5,000 people.