According to a report by the seismological network of the Geophysics Institute of Tehran University, the quake hit the area at 08:53 hours local time (0523 GMT).
The epicenter of the quake was located in an area 47 degrees in longitude and 32.5 degrees in latitude.
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.
Also in August, two quakes in Northwestern Iran claimed the lives of 306 people and injured more than 4500 others.
An earthquake measuring 6.2 on the Richter scale jolted Ahar in East Azerbaijan province on August 11. Almost an hour later another quake with magnitude 6 on the Richter scale jolted Varzaqan.
