China's Internet censors appeared to be blocking a number of overseas-based social media and messaging apps on Wednesday, after shutting down outspoken microblog accounts on the politically sensitive anniversary of Britain's handover of Hong Kong to China, technology experts and netizens said.
The popular messaging apps Line, KakaoTalk, and Viber had all stopped working, users reported, just weeks after China once more blocked Google's e-mail service.
It was unclear whether the blockage of the chat apps, which follows the blocking of the hugely popular WeChat smartphone app earlier this month, was linked to mass pro-democracy demonstrations in Hong Kong on Tuesday.
Nanjing-based database engineer Zhang Haoqi said the applications were still available through virtual private network (VPN) services, however.
He said that keyword searches on the name of the app were currently being blocked as "sensitive words" on China's tightly controlled Internet.
"It is probably being blocked [by the government]," Zhang said.
"There is probably some issue with this app if its name has become a sensitive word."
'Doubly sensitive' date
The blocking of the apps comes after Hong Kong's outspoken Apple Daily newspaper reported renewed cyberattacks on its website on Tuesday, when hundreds of thousands took to the streets to call for full democracy in the former British colony.
Online activist Wu Bin said he had had his account on the popular Twitter-like service Sina Weibo deleted.
"Yesterday was July 1, and there were closures all across Weibo ... it was a bloodbath; they went down one after another," Wu said.
Wu said the date is doubly sensitive, as it marks both the 93rd anniversary of the founding of the ruling Chinese Communist Party, and was also chosen as the date of the 1997 handover of Hong Kong, where it is now a day of traditional street protest.
"My account was shut down ... and all I did was write a comment on a post by a 50-center [government-hired propagandist] calling on people to congratulate the party on its anniversary," Wu said.
"They only want to hear flattery; they are incapable of hearing criticism," he said.
Internet user @banfengdeniu said China's Internet censorship was setting the country back two decades.
"The ability of technology to aid an effective lifestyle has been set back 20 years," the user wrote, pointing to existing blocks on Facebook, Twitter, YouTube, Google, and Flickr.
"They are even blocking Gmail, so why shouldn't they block LINE as well?" the user said.
Meanwhile, user @chenbingjieAlex added: "LINE is finished now; I guess it's collaborating [with censors]."
User content censored
China Internet censorship watchdog GreatFire.org said via Twitter that LINE had already gained a reputation for censoring user content within mainland China.
"Block of LINE [is a] warning signal to foreign net firms [with an] eye on China," the group tweeted on Wednesday. "Working [with the] authorities [means your] fingers get burned."
Earlier this month, Beijing extended a massive censorship operation to target popular social media sites, banning keyword searches linked to the 1989 Tiananmen Square military crackdown 25 years ago and a mass vigil in Hong Kong's Victoria Park.
On the popular Twitter-like service Sina Weibo and similar social media sites, censors quickly located and deleted posts containing the banned terms, while large numbers of accounts and chat groups were shut down, users said.
China's 620 million Internet users are forced to find ever more ingenious ways to elude the complex system of blocks, filters, and human censorship that is known colloquially as the Great Firewall, or GFW.
Reported by Yang Fan for RFA's Mandarin Service, and by Bi Zimo for the Cantonese Service. Translated and written in English by Luisetta Mudie.