Iranians have lined up outside polling stations to vote in a second round of parliamentary elections, with allies of President Hassan Rouhani seeking to wrest more seats from hardliners.
Rouhani's moderate and centrist allies made major gains in February 26 elections to parliament and a clerical body that will elect the next Supreme Leader, but failed to win a majority of the 290-member assembly.
The current parliament is dominated by hardline allies of Supreme Leader Ayatollah Ali Khamenei.
"People will vote for 68 undecided seats in constituencies that candidates failed to get 25 per cent of votes cast in the first round of the election," said Interior Minister Abdolreza Rahmani Fazli, state TV reported.
In a major blow to their hardline rivals, moderates won all 30 seats representing the capital city of Tehran in the first round of elections. Rahmani Fazli said the results will be announced by Sunday.
In a statement posted on social media on Sunday, reformist former President Mohammad Khatami called for a high turnout in the second round of elections to "repeat the epic", a reference to moderates' big gains in February.
Iranian media are banned from publishing the name or images of Khatami, who was president from 1997 to 2005, but Khatami managed to publish a five-minute video on social media ahead of February vote that changed the balance in favour of moderates.
Khamenei also has called for a high turnout, saying it will display Iranians' trust in the establishment.
The turnout was 62 per cent in February.
Sanctions were lifted in January in exchange for curbing Iran's nuclear program under a deal reached with major powers in 2015.