Upcoming vote will be seen, among other things, as a referendum on the landmark nuclear deal signed with world powers.
At least 30 people have been killed as flash flooding hit northwestern Iran on Saturday.
Torrential rains that began on Friday lashed East Azerbaijan province with state television showing images of rivers bursting their banks, flooded houses, and cars being swept away by the surging water.
“Thirty-five people have been killed in the floods,” head of Iran’s emergency response organisation Esmail Najar told ISNA news agency.
The districts of Ajabshir and Azarshahr were worst hit.
The East Azarbaijan Governor’s Office of Crisis Management said “16 bodies were found in Ajabshir city and 14 in the city of Azarshahr”.
The office’s Director-General Khalil Saei said Red Crescent workers, air ambulances, police and army forces have been deployed to assist in search-and-rescue efforts.