According to the Seismological Center of the Geophysics Institute of Tehran University, the tremor occurred at 4:42 hours local time (01:12 GMT).
The epicenter of the quake was located at 57.12 degrees longitude and 28.02 degrees latitude.
No report has so far been released on the likely casualties or damage to property.
Iran sits on major fault lines and is prone to near-daily earthquakes.
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