A woman shows the ink stain on her finger, to prove that she has voted, outside the Iranian consulate in central London June 14, 2013. [Photo/Agencies] ?

The ministry said in a statement that voters can cast their ballots until 23:00 p.m. local time (1830 GMT) on Friday. "It will not be extended further," said the statement.

Since 18:00 p.m. (1330 GMT) when the regular voting time for the presidential election was over, the Iranian Ministry has extended the voting hours three times.

According to Iran's election law, the regular voting time for the presidential election is 10 hours a day, but it can be prolonged in some major cities by the interior minister if he deems it necessary.

Iran's Supreme Leader Ayatollah Ali Khamenei cast his vote early Friday morning and opened the poll at 8:00 a.m. (0330 GMT).

Nearly 50.5 million eligible voters were expected to vote for six qualified candidates to choose the successor of Mahmoud Ahmadinejad.