Ali Larijani, the secretary-general of Irans Supreme National Security Council (SNSC) and the countrys chief nuclear negotiator, and al-Assad discussed bilateral and regional issues, state media reported.
The talks included the subjects of Iraq, Lebanon, and the Palestinian-Israeli conflict.
The two officials accused the United States of stirring tensions between Shiite and Sunni Muslims.
Larijanis visit to the Syrian capital had not been previously announced. His trip came a day after Iraqi President Jalal Talabani returned to Iraq from a landmark trip to Damascus.
Regional allies Iran and Syria are both accused by the U.S. of being state sponsors of terrorism.
