BEIJING • The Chinese authorities appear to have severely disrupted the WhatsApp messaging app in the latest step to tighten censorship ahead of a major Communist Party congress next month.
Users in China have reported widespread disruptions in recent days to the Facebook-owned service, which previously malfunctioned in the country over the summer.
Experts said the problems began on Sunday, but text messaging, voice calls and video calls appeared to be working again yesterday, though voice messages and photos were not going through.
WhatsApp provides message encryption technology that likely does not please the Chinese authorities, which closely monitor and restrict cyberspace through their "Great Firewall".
Many Chinese activists favour WhatsApp over local messaging apps because of its end-to-end encryption function.
China has tightened online policing this year, enacting new rules that require tech companies to store user data inside the country as well as imposing restrictions on what is permissible content.
Chinese cyberspace regulators said on Monday that they slapped "maximum" fines on major Chinese tech firms Baidu and Tencent for allowing the publication of pornographic, violent and other sorts of banned material on their social media platforms.
The amount of the fines was not disclosed.
Websites such as Facebook, Twitter, Pinterest and a slew of foreign media have been blocked for years.
The WhatsApp troubles emerged ahead of the Communist Party congress on Oct 18, when President Xi Jinping is expected to get a second five-year term as the party's general secretary.
"It smells like party congress pre-emptive blocking," said Mr Jason Ng, who researches China's Internet at the Citizen Lab at the University of Toronto. China usually steps up surveillance around major events, he said.
While the WeChat messaging app owned by China's Tencent company is more widely used in the country, many WhatsApp users complained about the disruptions.
"As we get closer to the party congress, I think (the) authorities will use more extreme censorship measures. The public knows that WeChat isn't safe," prominent Beijing-based activist Hu Jia told AFP.
"Me and other dissidents use WhatsApp to communicate 70 per cent of the time. For the few days WhatsApp was completely inaccessible, we didn't talk at all," he said.
Other users in China noted that the WhatsApp disruptions would make it difficult to work with clients abroad. WhatsApp declined to comment.