European Union foreign policy chief Catherine Ashton has expressed concern over a recent wave of arrests of journalists in Iran.
Ashton said in a statement that such actions would "constitute acts of politically motivated intimidation."
Some 14 journalists from several reformist newspapers and a semiofficial news agency were arrested over the weekend.
Iran's Intelligence Ministry has accused them of being members of "one of the biggest media networks" run by Western governments.
In a separate development, a number of Iranian journalists working abroad for international media, including RFE/RL's Radio Farda and BBC-Farsi, have been targeted with sophisticated online attacks.
Several of them have recently been the subject of fake Facebook profiles and blogs that post false and even scandalous information with the aim of discrediting them.