TEHRAN — In his clearest warning that political infighting by his subordinates must end, Iran’s supreme leader, Ayatollah Ali Khamenei, said Wednesday that their public disputes would be treated as treason.

Complaining that the increasingly open public fights between the executive branch of President Mahmoud Ahmadinejad and high-ranking officials in the legislative and judicial branches were providing ammunition to ‘‘foreign media and enemies,’’ the ayatollah, who has the last word on affairs of state in Iran, set the clearest red line ever to those running the country’s day-to-day matters.