The BBC news website has been blocked in China in an act of "deliberate censorship" over the posting of videos relating to the protests in Hong Kong.
It is the first time since December 2010 that an English-language news website has been completely blocked by authorities in China, in a move that has been condemned by the BBC's Global News director Peter Horrocks.
"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," Horrocks said in a statement.
"The BBC strongly condemns any attempts to restrict free access to news and information and we are protesting to the Chinese authorities."
China's strict internet censorship - often referred to as the Great Firewall of China - has previously seen major organisations and online services blocked in the world's most populous country.
Earlier this year, file-sharing site Dropbox was blocked in China, while Google, Facebook, Yahoo and Amazon have all experienced periodic blocks to their sites.
It is understood that censorship of the BBC website stems from a video posted online by the news organisation appearing to show Hong Kong police beating a pro-democracy protestor.
Police authorities in the region are currently investigating the incident.
The BBC and other foreign news channels already suffer from intermittent blackouts in China whenever reports of the Hong Kong protests are broadcast.
Protests in the former British colony started in September 2014 after Beijing decided to screen candidates for the first election in the territory, planned for 2017.