The quake was the strongest in 10 years to rock the region around Neyshabour, where it shattered windows and was followed by several aftershocks.
Iranian state television reported that residents in the stricken area fled their homes into the streets during the shaking, which was said to have lasted for just under 10 seconds.
The U.S. Geological Survey said the quake was centered about 6 miles northeast of Neyshabur and 420 miles east of Tehran.
The epicenter was also measured at the relatively shallow depth of only 9 miles.
While cracks appeared in the walls of some structures around Neyshabour, there were no reports of significant damage.