Image copyright AFP Image caption China has the world's largest online population

China has shut down several online news operations amid a crackdown on political and social news reporting, local media report.

News services run by some of China's biggest online portals, including Sina, Sohu, NetEase and iFeng, were shut for publishing independent reports instead of official statements, the media said.

The sites had seriously violated reporting rules, officials said.

China has tightened controls on online communications in recent years.

Most Chinese news sites are prohibited from gathering or reporting on political or social issues themselves, and are instead meant to rely on reports published by official media, such as state news agency Xinhua.

However, many news organisations had hired investigative journalists to produce their own reports, to cover major social issues and attract more readers and revenue.

Image copyright AFP Image caption Sina owns one of China's largest online portals

Now, several major online news columns, such as Sina's News Geek, Sohu's Click Today, and NetEase's Signpost, have all been closed, along with related social media accounts, newspapers Beijing Daily and the Beijing News reported.

They had "published large amounts of independently-gathered news reports, in serious violation of the rules", and could also face fines, the newspapers added.

News outlets in China operate under tight Communist Party control, with censorship and self-censorship common.

Thousands of cyber-police also watch the web and social media, and material deemed politically and socially sensitive is filtered.

In February, Chinese President Xi Jinping toured state media outlets, and said journalists must give absolute loyalty to the Communist Party.