Three major international broadcasters have strongly condemned Iran for what they call its deliberate electronic interference in their broadcasts.
The BBC, Deutsche Welle and Voice of America say the jamming began on Thursday as Iran marked the 31st anniversary of the Islamic Revolution.
They say Iran is broadcasting freely around the world while denying its own people programmes coming from outside.
Earlier, the United States accused Iran of using a near-total information blockade.
A state department spokesman says there are strong indications that the telephone network had been taken down, SMS messages blocked, and internet communication throttled.