Iran's Intelligence Ministry has accused more than a dozen journalists, arrested over the weekend, of being members of "one of the biggest media networks" linked to the West.
The ministry claimed the BBC, along with several Western governments, is running the network.
The BBC has denied the allegations as baseless.
The recent arrest of some 14 journalists from several reformist newspapers and a semiofficial news agency appears to be part of a campaign of repression
ahead of Iran's June 14 presidential vote.
In its statement, the Intelligence Ministry said it was possible that more journalists could be arrested or summoned as the investigation continues.
It also said some detainees could be released, since "they were probably unaware of links to abroad."
Rights groups have criticized the arrests.
Based on reporting by ISNA, BBC, and AFP