Iran's supreme leader, Ayatollah Ali Khamenei, has called on all Iranians to vote in Friday's elections, "even if for reasons they don't want to support the Islamic ruling establishment".

"They do want to support their country though. Everyone must turn out," Khamenei said on Wednesday.

Until recently a high turnout seemed unlikely. Since 21 May, when the guardian council announced the eight approved presidential candidates – excluding two prominent figures, the former president Akbar Hashemi Rafsanjani and Esfandiar Rahim Mashaei, a close ally of Mahmoud Ahmadinejad – the campaign had appeared to rouse little public interest.