General Mohsen Kazemeini said Iran, a key backer of the regime, feels an "obligation" to send "military advisers" to Syria to protect Shia shrines at the request of the Assad government.
Tehran acknowledges that Guard officers are on the ground in Syria in an advisory role, but denies it has sent combat troops, despite evidence to the contrary.
A number of Iranian soldiers have been killed in Syria, including high-ranking officers. A recent regime victory in Sheikh Miskeen was carried out with help of Iran-backed Hezbollah and military officers.
Wednesday's statement was the first time Iran has acknowledged training volunteer advisers, although the regime itself has consistently made illusions and has given thanks to Iranian support.
Analysts have noted that Syrian President Bashar al-Assad has neglected his self-purported Arab nationalist ideals and repeatedly bowed to Iran.
"Syria is not for those who live in it or those with Syrian citizenship; it is for those who defend it," he said in a speech last year, in an apparent reference to Iranian and Russian interference.
Iran has also dictated and scuppered deals between rebels and regime forces, including a deal for the end of rebel-imposed campaigns on Shia towns of Fuaa and Kefraya for an end to the regime campaign on Zabadani in August last year.
Reflective of wider Iranian policy on Syria, Iran demanded that civilians in Zabadani should be removed in return for relocating residents of Fuaa and Kefraya to Damascus.
The recent admittance coincides as the Syrian opposition have critisised the US for bowing to Iranian demands concerning Syria following a "catastrophic" meeting in Riyadh between Kerry and the head of the Syrian opposition's High Negotiation Council.
"Kerry carried with him clear dictates from Russia and Iran and threatened the Syrian opposition in the event of non-compliance," a high-level source in the Syrian opposition told The New Arab.
Relations between the US and Iran have improved since the historic nuclear deal last year which was criticized by many Syrians.
An activist in Damascus said at the time that while Iran has so far been "a great unseen supporter of Assad", after the deal it won’t be ashamed to help Assad "in front of the entire world".
Iranian military interference in Syria has recently been sidelined since Russia catapulted its air force into the conflict in September in order to back the regime.
Although relations between Iran and Russia have seemingly strengthened due to their shared shot-term aims in Syria, researchers have said that conflict may later emerge between the two powers due to differing motives for involvement.