A senior Iranian security official was expected in Damascus on Saturday for a meeting with President Bashar al-Assad, Iranian officials in the Syrian capital said.
Saeed Jalili, who heads the Supreme National Security Council, would also meet with Syrian Prime Minister Wael al-Halqi and Foreign Minister Walid al-Muallem, the officials told AFP on condition of anonymity.
Jalili, who last visited Damascus in August 2012, is also Iran's top nuclear negotiator and a close aide to supreme leader Ayatollah Ali Khamenei.
His visit was also confirmed by Tehran-based Al-Alam television channel, which reported that the trip would be important" -- although it did not elaborate.
It follows reported Israeli air strikes earlier this week near Damascus, which a US official said hit a military complex and missiles near the Syrian capital.
The Syrian army said previously that Israel's air raid at dawn Wednesday targeted a military research centre situated between Damascus and the Lebanese border.
Israel fears Syria's weapons may be transferred to close Damascus and Tehran ally Hezbollah, a powerful Lebanese Shiite movement, the US official said.
Key Damascus regional ally Iran has backed Assad's claim that the 22-month uprising against his regime is politically, financially and militarily backed by the United States, Turkey, Saudi Arabia and Qatar.
Outgoing US secretary of state Hillary Clinton accused Tehran of stepping up military aid to Damascus.
"The Islamic Republic's support to Syria... is based on principle," Jalili was quoted as saying by Iranian media on Thursday.