A large explosion was heard on Saturday near Lake Bakhtegan, near the city of Shiraz in southern Iran, local authorities said.
Speaking to Iran's state television, Gulamreza Gulami, crisis management director in the Fars province, confirmed that a huge explosion was heard in Shiraz.
The official rejected claims that the explosion was caused by a plane or helicopter crash in the region.
"The cause of the explosion is unknown, but according to the follow-up from Shiraz airport, there was no passenger plane or helicopter crash in the region," the official said.
"The army's air defense unit also confirmed the sound of a large explosion in the area. Local authorities, police and military units are investigating the issue," Gulami said.
There are no residential areas around Lake Bakhtegan.
At least two powerful explosions ripped through the southeastern city of Kerman on Wednesday, in close vicinity to the cemetery where Iran's former top military commander Gen. Qassem Soleimani lies buried.
Daesh on Wednesday claimed responsibility for the attacks in which 91 people were killed.
