Last year, China launched a campaign to clamp down on online rumour mongering and 'clean up' the internet. The crackdown has led to an exodus of users from Twitter-like microblog platforms such as Weibo Corp's Weibo after authorities detained hundreds of outspoken users.
The latest restrictions will likely affect hugely popular mobile messaging apps like Tencent Holdings Ltd's WeChat, which has almost 400 million users. Other instant messaging tools include Tencent's QQ, Alibaba Group Holding Ltd's Laiwang app, NetEaseInc's Yixin and Xiaomi Inc's Miliao.
Accounts that haven't been approved by the instant messaging service provider are forbidden to publish or reprint political news, the official Xinhua news agency said. It added that service providers must verify and publicly mark accounts that can publish or reprint political news.
Users must also sign an agreement with the service provider when they register, promising "to comply with the law, the socialist system, the national interest, citizens' legal rights, public order, social moral customs, and authenticity of information," Xinhua said.
These new regulations could have a similar chilling effect to the one seen on Weibo last year.
The rules "could cool down the traffic of WeChat public accounts and discourage journalists from setting up individual WeChat public accounts," said Fu King-wa, an assistant professor at the University of Hong Kong's Journalism and Media Studies Centre.
Tencent and Xiaomi declined to provide immediate comment by telephone. Alibaba declined to comment, while NetEase was not available for immediate comment by phone.
As apps like WeChat have grown in popularity, they have increasingly come under the ruling Communist Party's gaze.
"WeChat, and social media, are now truly mass media and regulated as such," said Duncan Clark, chairman of Beijing-based tech advisory BDA.
"There are challenges of course in regulating (WeChat), but the Party will never loosen up," said Clark.
On Thursday, South Korea said Chinese authorities had blocked messaging apps KakaoTalk, operated by South Korean KakaoTalk, and Line, a Japanese-based subsidiary of South Korea's Naver Corp, as part of efforts to fight terrorism, the first official explanation of service disruptions in China that began a month ago.
Other services like online video streaming sites run by Youku Tudou Inc, Sohu.com Inc, Baidu Inc and Tencent have also been targeted by censors in recent months.
Tencent shares were down 3.5 percent in Hong Kong trading on Thursday, versus a 0.8 percent drop in the Hang Seng Index.
© Thomson Reuters 2014