China's internet censors have shut down a number of discussion groups on the smartphone messaging app WeChat after users praised late Cuban leader Fidel Castro, who died last week, sources told RFA.
"At 3.30 p.m. today, Beijing time, the chat groups Ideology Salon, Constitutional Road, The Wind And The Rain, The East is Dawning, Consensus, and Towards a Republic, were all closed down," a WeChat user who asked to remain anonymous posted on Monday.
"At the same time, moderators Tang Zhe, He Zehong, and others lost their posting privileges."
Groups belonging to rights activists He Weifang, Zhou Xiaozheng, Mao Yushi, and others were also shut down, the post said.
Another source contacted by RFA said the closures came after a wave of online praise for Castro's Cuba, which had likely made the authorities "unhappy."
"There are a couple of red lines that can't be crossed online right now," the source said. "You can't say anything about our current leadership, and particularly not about [President] Xi Jinping."
"There has recently been a lot of discussion lately about our relative who just died overseas, so I think that was what triggered the closures of the groups," he said, in a veiled reference to Castro's death.
Xi paid glowing tribute to Castro via state broadcaster CCTV on Saturday.
"The Chinese people have lost a good and true comrade," he said in a statement read out by news announcers.
"Comrade Castro was a great man of our time ... History and people will remember him," Xi, who last visited Castro in 2014, said. "Comrade Castro will live forever."
Hu Ping, the New York-based editor of the Chinese-language monthly Beijing Spring, said Xi's praise for Castro is hardly surprising.
"They are all Communist Party leaders, after all, and they all support each other," Hu told RFA's Mandarin Service in a recent interview.
But he added: "All we really have to look at is how many people have taken huge risks to get out of Cuba, to see that Xi's appraisal of Castro has no basis in reality."
While China's relationship with Cuba was complicated by the Sino-Soviet split in the 1960s, ties have warmed since the death of late supreme leader Mao Zedong's in 1976.
And Castro appears to have something of a following behind the Great Firewall.
On the Twitter-like platform Sina Weibo, users commented on world leaders who praised Castro, including Philippines president Rodrigo Duterte and Canadian prime minister Justin Trudeau.
Duterte said Castro was "a revolutionary who, upon assuming his island’s highest political office, reasserted his nation’s dignity and self-worth, stood up against the West and capitalism."
And Trudeau issued a statement Saturday that called Castro "a controversial figure," but also praised him as "a legendary revolutionary and orator" and "a remarkable leader," causing a public outcry among Western media commentators.
Not, however, in China.
"[Trudeau]'s speaking the truth, and he gets attacked," wrote user @huxiangjingzhong, whose name means "mutual respect."
"It just goes to show that there is no such thing as freedom of speech anywhere in the world," commented user @changhe01. "Just look at Julian Assange and Edward Snowden."
"Now it's even affecting the Canadian prime minister and you don't think it's a reality?"
And @dadadadadeda mused: "When it comes to politics, Western public opinion is pretty powerful."
Hu, however, listed Castro's "very serious acts of wrongdoing," including going after capitalists, nationalizing state assets, and brainwashing intellectuals to reform their ideology.
"He also created an economic crisis, a disaster, [in the manner of China's Great Leap Forward [1958-1960]," Hu said.
Challenge to the system
Beijing scholar Wang Jiangsong said even the ruling Chinese Communist Party is unlikely to be able to tamp down all public comments that make it feel uncomfortable, however.
"If they shut down these chat groups, people can just form another one, and find somebody else to moderate them," Wang said. "Anyone can set up a chat group, so you can just get the same group of people back together again."
"This is a challenge to a political system that tries to completely regulate the internet," he said. "Such methods are clearly not going to work, unless they pull the plug on the whole network."
But Beijing-based constitutional scholar Chen Yongmiao said that it is merely a matter of time before the authorities catch up to chat apps.
"Every time a new technology emerges, they don't have time to crack down on it, so it appears that they are giving it more leeway," Chen said. "In fact, there is no relaxation; controls on freedom of speech have always been tight."
Chen said WeChat is now getting to the point where it can be shut down as quickly as anything else.
"Blogs, tweet platforms, chat apps, have all just been small oases in the desert," he said. "Maybe a new product will come out that will bring more people into the fight for democracy."
Reported by Qiao Long and Zhu Dan for RFA's Mandarin Service. Translated and written in English by Luisetta Mudie.