Authorities in Iran have arrested five people working for the BBC's Farsi-language service, Iranian state television reports .
The report on the channel's website said the group provided the British Broadcasting Corporation with video and negative news reports on Iran. The report did not identify them by their full names.
Iran has blocked the channel and accused it, alongside the British government, of fomenting the mass protests that broke out after Iran's disputed presidential election in 2009. Both deny the accusation.
The BBC's Farsi service has no office in Tehran.
Iran has detained many journalists and bloggers in recent years.