Miliband, arriving for talks in Luxembourg with EU foreign ministers, voiced "serious doubts" about the vote count which returned Mahmoud Ahmadinejad to power as Iran's president.
"The most striking thing though is that the events of recent days, the blocking of SMS messages, the closing down of TV stations the cancellation of rallies is in stark contrast to the openness, relatively speaking, of the election campaign itself," he told reporters.
"I think that in the very short term people will continue to focus on what seems to be state violence against its own people in Tehran and elsewhere."
Meanwhile, the BBC said the satellites it uses to broadcast BBC Persian television to Iran were being jammed.
London-based Amnesty International called for an investigation into "the shocking scenes of violence meted out by the security forces."
