The BBC's website was blocked in China Wednesday, hours after a video of Hong Kong police beating and kicking a pro-democracy protester began circulating online.
The move appears to be the first time the British broadcaster's English-language website has been completely blocked in China since December 2010, when it was inaccessible for days before the Nobel Peace Prize award ceremony for Chinese dissident Liu Xiaobo.
The BBC's Chinese-language website has been blocked in China since it was launched in 1999, aside from a few months around the time of the 2008 Beijing Olympics.
In a statement, BBC director of global news Peter Horrocks said the move "appears to be deliberate censorship".
"The BBC strongly condemns any attempts to restrict free access to news and information and we are protesting to the Chinese authorities," Horrocks said.
"The BBC provides impartial, trusted news to millions of people around the world, and attempts to censor our news services show just how important it is to get our accurate information to them," he added.
In a Twitter posting Wednesday, BBC's Asia bureau chief Jo Floto noted that Chinese authorities also have a "usual practice of blacking out BBC World during Hong Kong reports".
Charlie Smith, a co-founder of the anti-censorship group GreatFire.org, confirmed that the broadcaster's website was blocked in China on Wednesday.
China's Communist Party oversees a vast censorship system that aggressively blocks sites or snuffs out Internet and TV content and commentary on topics considered sensitive, such as Beijing's human rights record and criticisms of the government.
The New York Times and Bloomberg have had their websites blocked in China since they published investigations in 2012 into the family wealth of former premier Wen Jiabao and President Xi Jinping respectively.
As pro-democracy protests in China's semi-autonomous region of Hong Kong escalated late last month, online censors moved to block the photo-sharing app Instagram, which joined Facebook, YouTube and Twitter as popular social media platforms inaccessible in mainland China.
The blocking of the BBC's website came as a video of Hong Kong police beating a pro-democracy protester went viral on the Internet.
In the video, released by Hong Kong television network TVB, a group of six plainclothes officers are shown assaulting a handcuffed and unarmed protester for several minutes.
The footage sparked outrage and calls for prosecution from activists and lawmakers. Hong Kong's security chief said Wednesday the accused officers had been "removed" from their posts.
TVB's website remains accessible in mainland China, although Chinese-language links to reports on the video have been blocked.
CNN's website was also not blocked Wednesday, even though the Hong Kong police brutality video was the top item on the broadcaster's home page.
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