Turnout will be seen as a key measure of support for Iran's leadership at the time of a sanctions-linked economic downturn and diplomatic isolation.
Italian banks can not refuse their service on the basis of nationality but many Iranians facing banking difficulties say there is no other reasons being their accounts being closed.
Hundreds protested in Tehran on Monday after Italy's Andrea Stramaccioni quit as manager of Esteghlal FC because US sanctions prevent him from getting his salary.
Families of those held in Iran have accused Tehran of "hostage taking" and demanded governments take concerted action.
The national security adviser departed abruptly after President Trump suggested he might lift some sanctions as an incentive for Tehran to get to the negotiating table.
Iran has seized another foreign tanker in the Gulf, according to the country's state media.
Mohammad Javad Zarif said the move is meaningless as he has no property in the United States.
This is the first time Europe has seized a tanker at sea despite a ban on oil shipments to Syria since 2011.
From chickens to ID cards, US sanctions are changing daily life for many Iranians.
Denmark's Foreign Minister Anders Samuelsen said the EU was sending a "strong signal" after agreeing to enact sanctions against Iran's intelligence agency