The Seismological center of Isfahan province affiliated to the Geophysics Institute of Tehran University registered the main quake at 07:38 hours local time (0308 GMT).
The epicenter of the main quake, which was followed by at least 4 aftershocks ranging from 2.2 to 2.5 degrees on the Richter scale, was located in an area 50.52 in longitude and 33.49 in latitude.
There are yet no reports on the number of possible casualties or damage to properties by the quake.
Iran sits astride several major faults in the earth's crust, and is prone to frequent earthquakes, many of which have been devastating.
The worst in recent times hit Bam in southeastern Kerman province in December 2003, killing 31,000 people - about a quarter of its population - and destroying the city's ancient mud-built citadel.
The deadliest quake in the country was in June 1990 and measured 7.7 on the Richter scale. About 37,000 people were killed and more than 100,000 injured in the northwestern provinces of Gilan and Zanjan. It devastated 27 towns and about 1,870 villages.
