Iran's supreme leader says that Iranians should not serve the country's enemies by questioning the fairness of upcoming presidential elections.

The remarks by Ayatollah Ali Khamenei quoted Tuesday by state TV also appeared to be a warning to reformists who have in recent weeks stressed that the vote scheduled for June be free.

Iran wants to avoid a repeat of the unrest that followed 2009 presidential elections. Opponents of the winner, President Mahmoud Ahmadinejad, called them fraudulent.

Khamenei, who has final say on all state matters, says hostile powers "want to do something so that the elections are without the lively and massive participation of the people."

"All people should be careful that their remarks do not serve this desire of the enemy," he says.