China is banning users of Internet messaging services from posting political reports without permission, and demanding they promise to "uphold the socialist system", state media said Thursday.

China tightly controls the Internet, but its online population of 632 million has used messaging applications to push the boundaries of the ruling Communist party's restrictions on free speech.

Internet companies are required to ensure that users of online messaging services register with their real names, state broadcaster China Central Television (CCTV) cited the government's National Internet Information Office (NIIO) as saying.

Users will be required to agree to "seven bottom lines", including a vow to "uphold the socialist system", a euphemism for China's one-party dominated regime, when they register, CCTV said.

Hundreds of millions of Chinese use the Twitter-like Sina Weibo, and messaging app WeChat, among other online services.

The latest regulations appeared to be aimed at WeChat, an instant messaging platform that allows users to share text, photos, videos and voice messages over mobile devices.

Some foreign messaging apps, including KakaoTalk and Line -- both of which are owned by South Korean firms -- have also been blocked in China for several weeks, according to multiple reports.

South Korean authorities said Thursday that Chinese officials told them the move had been taken as an anti-terrorism measure. There was no confirmation from Beijing or in Chinese media.

The NIIO said individuals or companies running public accounts on services such as WeChat cannot post "political news" without official approval.

The creation of new public accounts -- which enable transmission to multiple recipients -- is also subject to official approval, it said.

The new regulations come as China continues a crackdown on online "rumours", which rights groups say is an excuse to punish those who publish information critical of the ruling party.

Hundreds of people have been detained during the campaign, while several bloggers have been handed lengthy jail sentences, resulting in a decline in use of microblogs.

Dong Rubin, a blogger known for criticising Communist Party officials, was sentenced to six-and-a-half years in jail as part of the campaign last month, state media said.

China in May targeted public WeChat accounts which are used to post news stories, accusing them of "spreading rumours". Several liberal-leaning accounts were forced to close.

China's rigorous control over the Internet includes the blocking of foreign websites such as Facebook, Twitter and YouTube using a system known as the "Great Firewall".