The Leader of the Islamic Revolution has warned the Muslim community against a plot to cause a sectarian rift among Sunnis and Shias. Speaking on the Shia-celebrated Eid al-Ghadir, Ayatollah Seyyed Ali Khamenei said the enemy views Muslim unity and the growing interest of Muslim nations in the Islamic Revolution as a threat and therefore makes every effort to foment discord among Shias and Sunnis. Eid al-Ghadir marks the anniversary of the Prophet Muhammad's (PBUH) last sermon, during which he appointed Ali ibn Abi Talib (PBUH), the first Shia Imam, as his successor. Sunni Muslims do not deny the sermon having taken place; they, however, do not celebrate the day and regard Ali (PBUH) as the fourth and last of the caliphs (successors to the prophet) and not an Imam. Addressing Iranians, the majority of whom are Shia, Ayatollah Khamenei said the enemy has been spending large sums on various schemes to pit Sunni and Shia against one another. "We have intelligence that an institution supported by the global arrogance funds the publication of certain books which insult the beliefs of Sunnis or Shias," the Leader added. Ayatollah Khamenei said the publication of books that are written to offend Shias and Sunnis would only help the US and Israeli cause against Muslims and the Islamic Revolution.