Syrian Foreign Minister Walid al-Moualem arrived in Tehran on August 4 for talks with Iranian and Russian officials aimed at ending the four-year-old war in his country.
Moallem will meet Mikhail Bogdanov, President Vladimir Putin's special envoy to the Middle East, before holding talks with Iranian Foreign Minister Mohammad Javad Zarif on August 5, Iranian media reported.
Iran and Russia have stood by Syrian President Bashar al-Assad during the civil war, whereas the United States and Gulf Arab allies have said Assad must leave office.
Iranian Deputy Foreign Minister Hossein Amir-Abdollahian suggested the chances of a diplomatic resolution of the war are growing.
"Fortunately, we see a change in the strategy of regional players in the Syrian crisis. If four years ago they believed war is the only solution, now they prefer to focus on diplomacy," Amir-Abdollahian was quoted as saying by the Fars News Agency.
In another diplomatic effort by Iran following agreement on a nuclear deal with world powers last month, Zarif suggested forming a regional committee to tackle the multiple crises in the Middle East.
"Nowhere in the world needs this mechanism more than...the Middle East," he said.