The quake was registered at 17:20 GMT on Friday 47 kilometres (29 miles) east of the city of Masjed Soleyman and the epicentre was located at a depth of 10 kilometres.
There have been no immediate reports about damage or casualties due to the earthquake and no tsunami threat has been reported.
Iran is located on major seismic faults and often experiences powerful tremors, with some of them being extremely devastating - like the 6.6-magnitude tremor that devastated the ancient city of Bam, killing almost 26,000 people in 2003.