Sporadic protests, sparked after the re-election of Iran President Mahmoud Ahmadinejad, have continued until early morning in Tehran, Press TV reported.
The protests which were resume for a second consecutive day on Sunday continued until Monday morning, media reports say.
President Ahmadinejad, who marked a landslide victory on Friday, has described such protests as a 'natural outcome' of a hotly contested election.
"The election is like a football match played by two teams. The loser should just let it go," President Ahmadinejad said.
"The fact that some protest and question the election results is not important. It is rather natural, because they thought that they would win but they did not," the president said Sunday. "So, their sadness is understandable," he said.
All the other presidential candidates; Mir-Hossein Mousavi, Mehdi Karroubi and Mohsen Rezaei, have described as 'incredulous' official results released by the Interior Ministry.
The Interior Ministry announced that Ahmadinejad has won about 65 percent of the vote and his main rival, Mousavi has only managed to win 33 percent of the ballot.
The three have voiced their concerns about the official results and have lodged complaints with the Guardian Council, which supervises the election.
President Mahmoud Ahmadinejad has ruled out any 'irregularities'.
Mousavi has backed his supporters' right to protests, but has also emphasized that they should 'avoid violence and confrontation', while urging them to remain peaceful.
Supporters of Mousavi have also asked for permission to hold a peaceful march on Monday in central Tehran. However, it is not known whether the officials have authorized the rally.