The Iranian Government is jamming BBC broadcasts to the country after President Mahmoud Ahmadinejad's disputed re-election, the director of the World Service has said.
Peter Horrocks said audiences in Iran, the Middle East and Europe could be affected by the electronic jamming of satellites used to broadcast the BBC Persian TV signal to Iran.
He said: "It seems to be part of a pattern of behaviour by the Iranian authorities to limit the reporting of the aftermath of the disputed election."
He added: "In Tehran, John Simpson and his cameraman were briefly arrested after they had filmed the material for a piece.
"And at least one news agency in Tehran has come under pressure not to distribute internationally any pictures it might have of demonstrations on the streets in Iran."
The BBC launched its Persian-language television channel in January despite it being described by an Iranian minister as contrary to his country's "security".
Gholam Hossein Mohseini Ejehi was quoted by Iran's official IRNA news agency as saying the country would take measures against the channel.
He said: "We don't consider this channel to be appropriate for our security. We will take the necessary measures in this regard."
Last year, an Iranian MP accused the BBC of using the channel to recruit spies. Mohammad Karim Abedi said the corporation was planning on setting up an intelligence network using the launch of the channel as cover.
A BBC spokesman said its only goal was to report on world events in an impartial and editorially independent manner.
