It was the latest incident adding to regional tensions and fears of wider conflagration during the Israel-Hamas war in Gaza.
The strike in Damascus on Saturday killed five members of the Islamic Revolutionary Guard Corps (IRGC), the military force said. Iranian media later reported the victims included the group's intelligence chief for Syria, and his deputy.
Mourners carried aloft coffins bearing some of the victims, draped in colours of the Iranian flag, before a stage bearing pictures of IRGC General Qassem Soleimani who was killed three years ago by the United States.
A funeral dirge sounded.
State media reported that funeral processions were planned for three of the five IRGC members killed.
Asked about the strike, Israel's military said it does not comment "on reports from the foreign media."
The Syrian Observatory for Human Rights war monitor reported at the time that the strike hit the Damascus neighbourhood of Mazzeh where leaders from the IRGC and pro-Iranian Palestinian factions live.
A total of 13 people were killed, added the British-based monitor which has a network of sources in Syria.
The strike came four days after the IRGC said it hit an Israeli "intelligence headquarters" in Arbil, the capital of Iraq's autonomous Kurdistan region.
Baghdad said the missiles struck a businessman's family home.
Iran also hit alleged Islamic State group targets in Iraq's western neighbour Syria.
In a statement carried by Iran's official IRNA news agency, the IRGC said its Iraq strike was "in response to the recent vicious actions of the Zionist regime (Israel) which martyred the commanders of the Revolutionary Guards and the resistance front."
Iranian state media blamed an Israeli missile strike.
In early January a strike in the southern Beirut stronghold of Lebanon's Iran-backed Hezbollah movement killed the Hamas deputy leader, Saleh al-Aruri. A US defence official has told AFP that Israel carried out that strike.
Days later, a strike in southern Lebanon killed Wissam Tawil, the highest-ranking Hezbollah member to be killed since the war began between Israel and Iran-backed Hamas. Hezbollah blamed Israel.
