For nearly two hours on Sunday, dissident artist Ai Weiwei was able to maintain a Twitter-like microblog account, briefly raising hopes the Chinese government had relaxed some of its tight control over online expression.
Ai's first microblog post said: "Testing. Ai Weiwei. March 18, 2012."
Ai's account on Sina, the operator of China's most popular microblogging platform, drew 10,680 followers in that brief period, he told Reuters on Monday, including the jubliant-sounding comment: "The moment has come. The skies have changed in China."
Shortly afterwards, however, the account was inaccessible, apparently deleted by government censors.
Ai is a prominent social critic who was detained without charge last year for 81 days until his conditional release in late June. He said he used his social security number to register the microblog account after discovering that his name was unexpectedly no longer blocked.
"The controls are very strong," Ai told Reuters by telephone. "They (the government) are very insecure, they are not ready for any kind of change."
It was unclear what caused the crack in China's "Great Firewall" as microblog operators such as Sina comply with government orders and monitor content, blocking and removing comments deemed unacceptable or too sensitive.
Repeated calls to Sina went unanswered.
China heavily filters the Internet and blocks foreign social networking websites such as Facebook and Twitter, fearing that unfettered access would lead to instability.
The deletion of Ai's microblog, or weibo in Chinese, came after new regulations went into effect on Friday requiring Beijing-based microbloggers to register using their real identities.
Officials said the new rules are meant to curb rumours, vulgarities and pornography, but many users say the restrictions are aimed at muzzling the often scathing and raucous microblog chatter in a country where the Internet offers a rare opportunity for open discussion.
Ai said his account was deleted just past midnight on Monday, replaced with a message that read: "Error. Invalid Weibo user".
He said this was the first time he had succeeded in creating a weibo account. Ai is active on Twitter and has over 131,000 followers.
Since his release from detention, Ai has ignored efforts to silence him and has instead become a rallying point for dissidents and activists who have been harassed and arrested since a government crack down on opponents began last year.
Ai is a vocal critic of the Communist Party, who has spoken out on everything from the award of the 2010 Nobel Peace Prize to Chinese dissident Liu Xiaobo to Internet curbs.
Even after Ai's weibo account was deleted, some supporters held out hope.
"Ai Weiwei, when can you speak up on Weibo?" a user called Arizona_Hal wrote on Sina's microblogging website, where users could still search for the artist's name on Monday.
Copyright Thomson Reuters 2012