The attack targeted the vehicle as it was carrying the boxes out of a polling station in the Jakigur Rural District of Rask County in Sistan and Baluchestan Province on Saturday, Tasnim News Agency reported.
An investigation has been ordered into the incident, further details about which are yet to emerge.
The incident took place after midnight local time (20:30 GMT on Friday), the deadline for the voting process in the country’s snap presidential elections.
The election was called after President Ebrahim Raisi was martyred along with seven others on May 19, when the helicopter carrying them crashed in northwestern Iran.
More than 61 million Iranians have been eligible to vote at 58,000 polling stations throughout the Islamic Republic.
The race is contested by Saeed Jalili, a former lead nuclear negotiator, Mohammad Baqer Qalibaf, Iranian Parliament speaker, Mostafa Pourmohammadi, former interior minister, and Masoud Pezeshkian, former health minister.
