Iranians are voting in elections in an exercise widely expected to result in a more hardline parliament loyal to the country's supreme leader.
It is the first such poll since the US renewed sanctions over Iran's nuclear programme, battering its economy.
Thousands of moderate would-be candidates were barred from running for not meeting strict election criteria.
Observers say authorities will be hoping for a high voter turnout as a sign of support for the regime.
Critics of Iran's rulers have called on citizens to boycott the polls as a way of showing their opposition to what they say is widespread repression of human rights and intolerance of dissent.
