The TV says the quake struck in Shonbeh on Thursday morning, at 04:01 a.m. local time (Wednesday 23:31 GMT).
Last April, a magnitude 6.1 quake killed dozens and injured hundreds in the same district but authorities said it did not damage the nearby nuclear reactor in Bushehr, about 96 kilometers (60 miles) northwest of Shonbeh.
Iran sits on a series of seismic fault lines and experiences one slight earthquake quake a day on average.
In 2003, some 26,000 people were killed by a magnitude 6.6 quake that flattened the historic southeastern city of Bam.
