The Seismological center of Bushehr province affiliated to the Geophysics Institute of Tehran University registered the quake at 15:14 hours local time (1044 GMT).
The epicenter of the quake was located in an area 62.03 degrees in longitude and 28.04 degrees in latitude.
Many houses in rural parts of the province are made of mud brick, which can easily crumble in a quake.
Iran sits astride several major faults in the earth's crust, and is prone to frequent earthquakes, many of which have been devastating.
A 6.1 magnitude quake struck Bushehr province South of Iran last Tuesday killing at least 39 people and injuring 850 more as it devastated small villages. The epicenter of earthquake was located in the town of Kaki, 60 miles (96km) Southeast of Bushehr.
The nearby Bushehr nuclear plant remained undamaged.
The worst in recent times hit Bam in southeastern Kerman province in December 2003, killing 31,000 people - about a quarter of its population - and destroying the city's ancient mud-built citadel.
The deadliest quake in the country was in June 1990 and measured 7.7 on the Richter scale. About 37,000 people were killed and more than 100,000 injured in the northwestern provinces of Gilan and Zanjan. It devastated 27 towns and about 1,870 villages.
