The magnitude-5.5 earthquake occurred in Khorasan province, near the border with Afghanistan, at 8:38 p.m. local time.
A regional deputy said the earthquake had damaged buildings in rural areas and cut electricity and telephone communications.
Witnesses said thousands of people took to the streets after the quake in fear of an aftershock.
According to state television, 12 villages were affected.
In 2003, a violent earthquake slammed south-eastern Iran, killing 26,000 people.