Iran's police chief has again warned citizens against cooperating with foreign media, and accused the BBC and Voice of America of serving British and US intelligence services.

'All those who work with foreign services by sending them news, reports, pictures and films should know that their behaviour is monitored,' Esmail Ahmadi Moghaddam said in comments carried by local news agencies.

'They should not think they are too smart. We want them to return and correct their behaviour,' he said, effectively telling them to end their cooperation.

'The BBC is the medium of MI6 and VOA is the medium of the CIA, while some people contact them and make statements against Iran,' he said.

The two news channels have Persian services watched by many across Iran despite a ban on satellite television and the government jamming signals.

Iran has accused the two broadcasters of inciting unrest and anti-government protests in Iran as it blacklisted them along with dozens of other international organisations in January.