Syria condemned what it described as a "fascist Israeli aggression" targeting the Iranian Consulate in the capital Damascus on Monday.
Foreign Minister Faisal Mekdad, in a phone call with his Iranian counterpart Hossein Amir-Abdollahian, reiterated Syria's support to Iran following the attack, the state news agency SANA reported.
"Syria stands by Iran against assaults that reflect Israel's state of hysteria as a result of its miserable failure in its war against the Palestinian people in Gaza," said Mekdad, according to SANA.
Amir Abdollahian, for his part, underlined the position of both Iran and Syria "in standing together in the face of the Israeli brutality that crossed all limits".
Early Monday, General Mohammed Reza Zahedi, a senior commander of the IRGC's Quds Force in Syria and Lebanon, was killed in a strike that destroyed the Iranian consulate building next to the Iranian Embassy, the state-run IRNA news agency reported.
General Zahedi was a veteran IRGC commander who previously commanded the IRGC's ground force and air force and also served as the deputy commander of the IRGC's military operations.
There are also unconfirmed reports about the killing of General Rahimi, who served as General Zahedi's deputy, and Gen. Hossein Amirullah, head of the IRGC general staff in Syria and Lebanon.
The missile strike reportedly targeted a building that served as the Iranian Embassy's consular affairs department as well as the residence of the Iranian ambassador.
Iranian Ambassador in Damascus Hossein Akbari said the building was attacked with F-35 warplanes and six missiles, killing several Iranian military undersecretaries. He put the death toll from the attack at between five to seven people.
Akbari said the attack is against all international conventions and will see a "decisive response."
The attack came amid heightened tensions in the region in the wake of the Israeli onslaught on the Gaza Strip, which has killed more than 32,800 Palestinians and spawned the worst humanitarian crisis.
