Mohammad-Reza Sheibani and Siniora discussed the latest political and regional developments in Lebanon during their meeting on Tuesday, the official news agency IRNA said.
Regional allies Iran and Syria are both accused by the United States of being state sponsors of terrorism.
The UN Security Council decided in 2007 to set up a tribunal to prosecute the killers of former Lebanese Prime Minister Rafik al-Hariri, who was assassinated by a truck bomb on 14 February 2005.
Saad al-Hariri, the Majority leader in the Lebanese Parliament and the son of Rafik al-Hariri, accuses Syria of orchestrating the murder.
In February, Saad al-Hariri chided Iran and Syria for meddling in Lebanons political affairs.
“We are faced with the political and terrorist presence in Lebanon of the Syrian and Iranian regimes, but we will not sit by and watch. … If confrontation is our destiny, then we stand ready”, al-Hariri said on Feb. 7.
Due to factional feuding between al-Hariris Western-backed majority and the Hezbollah-led opposition, Lebanon has been without a president since November 2007 when the term of Syrian ally Emile Lahoud ended.
On Monday, an attempt to select a new President was postponed for the seventeenth time since Sep. 25. Army chief General Michel Sleiman has been slated for the post. The next attempt to select a President will take place on April 22.