New Iranian President Hassan Rowhani promised Syrian Prime Minister Wael al-Halqi on Sunday that there would be no change in the two countries' close alliance, Syrian state media reported.
"No force in the world can shake the solid, strategic and historic relations that bind the two countries in friendship," Rowhani told Halqi, who was in Tehran for the Iranian president's swearing-in.
"Syrian-Iranian relations are based on understanding and a common destiny," the Syrian Arab News Agency quoted him as saying.
The new president pledged "Iran's unwavering support for the Syrian people and government, in order to restore stability, face up to challenges, support efforts for reform and find a peaceful solution to the crisis."
The two governments have been close allies since the 1980 invasion of Iran by Saddam Hussein's Iraq, when Damascus took Tehran's side in the ensuing eight-year war.
Iran has been the main regional ally of President Bashar al-Assad's regime in its efforts to defeat an uprising against his rule that erupted in March 2011, sparking a conflict in which the UN says more than 100,000 people have died.
Halqi handed Rowhani a letter from Assad in which he "insisted on reinforcing the strategic relations" between the two countries, SANA said.
He said the two governments had the "will to face up to conspiracies of the West, the United States and their tools in the region, who are seeking to weaken the axis of resistance".
The last was a reference to the alliance between Damascus, Tehran and Lebanese Shiite militant group Hezbollah, whose fighters have openly intervened in the Syrian conflict since late April.