The BBC has accused China of "deliberate" satellite jamming of the BBC World News channel in recent days, to block the corporation's coverage of "sensitive" stories.
In a post on the BBC editors' blog to coincide with World Press Freedom Day, BBC global news director Peter Horrocks said there had been "deliberate electronic interference" with the channel, which has been reporting on the story of Chen Guangcheng, the blind Chinese civil rights activist who escaped house arrest and fled to the US embassy in Beijing.
Horrocks wrote: "This deliberate electronic interference of the channel's distribution signal is just the latest in a long line of examples to block our impartial news and prevent it reaching audiences.
"The BBC's Chinese language website has been consistently blocked in China, apart from a brief respite during the 2008 Beijing Olympics, and our radio broadcasts in Mandarin were historically subject to persistent frequency interference for decades.
"We strongly condemn these acts of censorship and harassment. The BBC has a long history of standing up to these attempts to prevent access to free media. This includes working closely with other international broadcasters to highlight these issues and encourage concerted international action."
Last year, the BBC complained of persistent attempts by the Iranian authorities to block access to the BBC Persian TV channel, and intimidation of the families of BBC Persian's London-based staff.
Horrocks added: "We repeat the call on international governments and the relevant regulatory bodies to put maximum pressure on those who seek to block access to trusted and independent news."