Assad, on his second trip to Iran since President Mahmoud Ahmadinejad took power in August 2005, Sunday met supreme leader Ayatollah Ali Khamenei and Iran's top security official Ali Larijani, official media reported.

The Syrian president had on Saturday met with Ahmadinejad, warning against the dangers of disunity between Sunni and Shia Muslims, in particular in multi-confessional Lebanon and Iraq.

"We should cooperate and work to make the public aware of the sinister aims of the United States and the Zionists," Assad said in his meeting with Ahmadinejad, according to the state-run IRNA news agency.

"Iran and Syria support the peoples of the region and the enemies will only reach their goals by creating pessimism and disunity amongst Muslims," he added.

Ahmadinejad agreed that "we should be careful about the enemies' efforts to create division and conflict amongst Muslims and make sure they do not reach their sinister goals.

"Under the current conditions it is necessary that Islamic countries preserve their vigilance, unity and wisdom to prevent the establishment of new conspiracies," he added.

Accompanied by Foreign Minister Walid Muallem and Vice President Faruq al-Shara, Assad also met former president and current head of Iran's top political arbitration body Akbar Hashemi Rafsanjani. He was due to leave Iran later Sunday.

"Creating conflict between Shias and Sunnis in Iraq and Lebanon is the final card that America and its allies have... they try to cover their failure with false propaganda," Assad told Rafsanjani.

Assad was the first world leader to visit Ahmadinejad following his election victory -- just five days after he took office -- and relations have remained strong ever since.

The Iranian president visited Damascus in January 2006, where he held talks with Assad and the Syria-based political leaders of Palestinian militant groups.

Assad's latest visit to Tehran comes at a time when both Syria and Iran have been accused by the US of "meddling" in the region. Both vehemently deny the charges.