"Therefore, the Muslim governments and nations, particularly political and cultural elites, intellectuals as well as theologians must reveal the truth to the Muslims," Khamenei was quoted as saying.
The supreme leader made the remarks at a meeting with some Iranian officials and foreign ambassadors to Iran.
He urged Muslims to "focus efforts on following Islam, maintaining and strengthening unity and brotherhood, and (practicing) disobedience to the great powers headed by the United States," according to Press TV.
The Iranian leader also described the disagreement among Muslim nations as a lethal poison.
"The principal issue of the Muslim world is (the issue) of al- Quds (Arabic for Jerusalem) and the oppressed Palestinians, which has come to the fore as a result of the Islamic awakening," Khamenei added.
Earlier on Sunday, Khamenei branded the United States and the Israel the "enemies" of the Muslim nations and said that they are complicating their plots against Muslims day by day. (C003)