China virtually shuts WhatsApp ahead of leadership rejig

China has partially blocked the popular messaging service WhatsApp, in what is seen a tightening of the grip on the internet by authorities ahead of a major leadership reshuffle in Beijing.

According to the South China Morning Post, most of the affected users said they could not send or receive photos using the chat app, which is owned by Facebook, without a virtual private network.

VPNs are used to skirt Beijing's censorship system – which blocks websites with information that could be critical of the Communist Party such as YouTube, Twitter and foreign news sites – by rerouting internet traffic elsewhere. But some reports say even VPNs were being blocked.

In a test conducted by the newspaper on Tuesday afternoon, two users who registered with mainland Chinese mobile numbers were unable to send videos or pictures to each other via WhatsApp.

According to The Guardian, photo, video and voice messages sent by the London newspaper from Beijing were all blocked on Wednesday, but text messages were not affected. But dozens of users in China complained of a total ban on sending any type of messages on WhatsApp.

The block appeared sporadic, similar to when Chinese authorities first banned Google's Gmail in 2014 before instituting a total blackout.

The ban comes as Chinese officials are preparing for a twice-a-decade leadership shuffle later this year, with various factions within the Communist party jockeying for control of key positions and president Xi Jinping likely to further consolidate power.

China operates the world's largest censorship system, known as the Great Firewall, blocking thousands of websites including popular platforms such as Facebook, Google, Instagram, YouTube and a host of foreign news outlets.

Xi, who came to power five years ago, has pushed for tighter government controls on what information Chinese citizens inside the country can access in what the government dubs ''cyber sovereignty''. Recent months have seen Beijing restrict live streaming video apps, online video content, celebrity news and VPNs.

In China, WhatsApp pales in popularity compared with homegrown messaging service WeChat, which boasts more than 900 million users. But the American app is increasingly being used by Chinese concerned about privacy or those communicating with friends or business contacts abroad.

''By blocking WhatsApp, the authorities have shut down one of the few remaining free and encrypted messaging apps but, more importantly, they have also limited the ability for Chinese to have private conversations with their peers,'' a Chinese censorship researcher known only by the pseudonym Charlie Smith told The Guardian in an e-mail.

''While the internet freedom community continues to develop unique and innovative circumvention tools we are doing very little to fight the climate of fear that Xi Jinping has manufactured in China.''

Before this week's ban, WhatsApp was the only service owned by Facebook still accessible within China. The popular social network has been blocked since ethnic riots in China's far west in 2009, while Instagram was banned during pro-democracy protests in Hong Kong in 2014.

Mark Zuckerberg, the Facebook boss, has made a high-profile push to get the company's services unblocked, showering praise on Xi and other Chinese officials, but has little to show for his efforts so far.

Chinese authorities previously blocked messaging app Telegram after it became popular with the country's human right lawyers.

The death of jailed Nobel peace prize laureate Liu Xiaobo last week also sent censors into overdrive, as they scrambled to block any commemorations on social media, even reaching into private messages on WeChat to block content.

Chinese censors were able to block messages and images in real time sent in private one-on-one chats in WeChat, according to a report by the University of Toronto's Citizen Lab.

China plans to block ''unauthorized'' VPNs, a common tool to evade censorship, starting in February 2018 and several domestic providers have already been forced to shut down.