Loud blasts were heard in several cities in western Iran including Kermanshah, Sanandaj and Ilam early on Sunday, according to local news agencies and eyewitnesses on social media.
According to the local authorities, the nature of the blasts was not immediately known.
The governor of the town of Asadabad claimed that a "terrifying sound" was heard, but its origin was not clear, the semi-official news agency Fars reported.
"Initially it was thought it was the sound of thunderstorms due to the weather conditions, but this possibility was ruled out," the official said.
"The intensity of the sound in some places was such that doors and windows of houses shook and people left their houses," the Rokna news website said on its Telegram channel.
Tensions between Iran and Israel have been increased, while Tehran has been holding indirect talks with Washington on reviving the 2015 Iran nuclear deal with world powers.
Israeli leaders have long threatened military action against Iran to stop the country from achieving nuclear weapons.
