“They should respect the right, that is also in the Iranian constitution, for peaceful manifestations,” said Bildt, whose country takes over the European Union presidency on July 1.
“Certainly the use of lethal violence against peaceful demonstrators is never tolerated in any country,” he said, as Iranian radio reported hundreds of arrests following weekend clashes in Tehran which left 10 people dead.
Following statements by EU leaders at a Brussels summit last week, the Iranian foreign ministry summoned the charges d’affaires from the 27 member nations of the bloc.
Tehran has accused many Western nations of interference.
“If ambassadors are called in, I think this is a sign that the message has been heard, and that’s good from that point of view,” Bildt told reporters.
“I would look forward to hearing if they have anything concrete to say, that is in the realm of a dialogue on the subjects that we’ve raised from the European Union point of view,” he added.
The protests over the June 12 election are the biggest popular upheaval in Iran since the 1979 Islamic revolution.
Opposition leader Mir Hossein Mousavi, who has led protests over what he says was a rigged election that returned Mahmoud Ahmadinejad to power, has urged supporters to continue to demonstrate.