Magnitude 6.3 quake near Elassona saw people run from their homes in panic with tremors felt across the country.
A magnitude 5.9 earthquake has struck Iran’s southern province of Bushehr, where a nuclear power plant is located, but there were no immediate reports of considerable damage.
At least five people were injured, Iran’s state-run IRNA news agency reported. The epicentre of the earthquake on Sunday was the town of Rig.
Hospitals in nearby cities and provinces were put on alert with rescue teams and 50 ambulances sent to the area, a regional official told state TV.
Electricity and landline telephone and internet in the regional city of Gonaveh were cut off “and people are taking to the streets for fear of earthquakes”, semi-official news agency Tasnim reported.
An Iranian government official told Reuters news agency there were no reports of damage at the Bushehr nuclear complex, situated on Iran’s Gulf coast.
The earthquake was centred 100km (60 miles) away from the plant and was relatively shallow – only 10km (6 miles) deep, according to Iranian media which also reported nine aftershocks and posted pictures that showed collapsed mud-brick walls in some villages.
Two people were injured in Gonaveh and were being taken to hospital, state media quoted the head of the Bushehr University of Medical Sciences, Saeed Kashmiri, as saying.
Crisscrossed by major fault lines, Iran is one of the most earthquake-prone countries in the world.
In 2003, a magnitude 6.6 earthquake in Kerman province killed 31,000 people and flattened the ancient city of Bam.