According to a report by the Seismological Center of the Geophysics Institute of Tehran University, the earthquake hit Larijan area at 04:25 local time (2355 GMT Saturday).
The epicenter, with a depth of 8 km, was determined to be at 35.95 degrees north latitude and 52.30 degrees east longitude.
No report on possible damage caused by the earthquake has been published.
Mild earthquakes can cause high number of casualties in populated areas as in rural areas houses are built using mud.
In view of frequent tremors in the country the regime has no plan to improve the state of housing in accordance with standards for quake zones.
The worst in recent times hit city of Bam in Kerman province in December 2003 that a killed 31,000, quarter of its population.