A quake of magnitude 6.3 struck near Iran's only nuclear plant in the city of Bushehr on Tuesday, killing 37 people and injuring 850 others.
The quake destroyed several homes and two small villages on Tuesday night, but the nuclear plant was not damaged.
"Due to the intensity of this earthquake, this tragedy has deepened and we have seen the destruction of many homes in the region, the deaths of 37 people and more than 850 injured," the governor of Bushehr province, Fereydoun Hassanvand, told Mehr news agency.
The earthquake was centered at about 94km (58 miles) of South East of Bandar Bushehr, 103km (64mi) WSW of Firuzabad and 129km (80mi) South of Kazerun, the US Geological Survey (USGS) reported.
The 6.3 magnitude quake occurred at 11:52 GMT at a depth of 10km (6.2 miles), according to USGS.
Mahmoud Jafari, the nuclear plant chief, told Mehr news that the plant could resist earthquakes of up to magnitude eight.
Ebrahim Darvishi, governor of the worst-hit district, Shonbeh, said that water flow and electricity lines were cut in many places due to the quake.
The earthquake was also felt across the Persian Gulf in Qatar, Bahrain and Dubai, where offices were evacuated immediately as a precaution.
Several houses made of mud-brick in rural areas of the province collapsed in the quake. According to Hassanvand, nearly 700 homes were destroyed on Tuesday.
"We could clearly feel the earthquake," Nikoo of Bushehr, who only wanted to give her first name, told Reuters. "The windows and chandeliers all shook."
According to Reuters, residents were traumatized by at least 16 aftershocks after initial quake.