The biggest of the tremors measuring 3.1 on the richer scale struck the city of Varzaqan, East Azarbaijan Province, at approximately 02:29 local time (2259 GMT Wednesday night).
The epicenter of the main quake, which was followed by at least 20 aftershocks ranging from 2 to 3.1 degrees on the Richter scale, was located in an area 46.5 in longitude and 38.4 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.
Around three months ago, two quakes in Northwestern Iran also 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 at 16:00 hours local time (1130GMT) on August 11. Almost an hour later another quake with magnitude 6 on the Richter scale jolted Varzaqan at 17:04 hours local time (1234GMT) in the same province.
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Several tremors jolted parts of Northwestern Iran on Thursday, one day after a quake measuring 5.1 on the richer scale struck the area and injured over 50 people.
News ID 183293
