"Adventurous efforts and interventions by the United States and the Zionist regime are the main cause of the continuous chaotic situation in Lebanon," foreign ministry spokesman Mohammad Ali Hosseini said.
"Unfortunately, part of the political plot which was predicted … has been executed," said Hosseini, who was quoted by ISNA and Fars news agencies.
"We hope that those who have been responsible for creating this situation exert the effort needed to restore stability and calm to Lebanon," he added, without elaborating.
Hezbollah gunmen seized control of west Beirut on Friday after a third day of battles with Sunni militants loyal to the Western-backed government that has killed at least 11 people, Lebanese security official have said.
Hosseini said Iran will pursue "tireless efforts … to help different political groups reach an understanding."
The United States and Israel have repeatedly accused Iran of arming and financing Hezbollah in a bid to destabilise Lebanon — a charge the Islamic republic has constantly denied.
The United States has condemned the violence in Lebanon and demanded that Hezbollah, which is also backed by Syria, stops its "destructive activities."
Israeli President Shimon Peres on Friday claimed the violence in Lebanon was fomented by Iran to further what he said was Tehran's goal to control all of the Middle East.
