The BBC launched its Persian-language television channel today, 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 month, 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.
World Service director Nigel Chapman, speaking at the launch of the channel, said: "This is a BBC channel. It has the same aims and values as all the other BBC news outlets.
"We aim to be authoritative and impartial in our journalism. In this respect we want to hear from Iran's leaders, opinion-formers and citizens where their views are relevant. This is something we have made clear to the authorities in Iran and we will do our best to facilitate this within our limited capabilities.
"We aim to be trusted for the accuracy, editorial independence and expertise of our journalism."
Mr Chapman and BBC Global News director, Richard Sambrook, have visited Iran in the past 18 months to discuss the channel's launch with the authorities.
Despite that, Iran has refused to issue press accreditation to the channel's correspondents.
The BBC does have an accredited English-speaking bureau in the Iranian capital Tehran.
BBC Persian TV will be broadcast from London every day from 1.30pm to 9.30pm UK time.
It is the broadcaster's second foreign-language TV channel after the launch of BBC Arabic last year.
The BBC has run a Persian-language radio service since 1940.
It also operates a Persian-language news site online, although access to some of that output has been blocked by the Iranian authorities.
BBC Persian TV can be seen in Iran, Afghanistan and Tajikistan.
It can also be received in Britain and most of the Persian Gulf via satellite and cable services.