The soldiers were reportedly killed in the Khan Touman area 15km southwest of Aleppo in fighting with Jabhat al-Nusra, also known as the al-Nusra Front, who had seized control of the area on Friday.
Most of the soldiers killed belonged to the Fatemiyoun Brigade, according to the Iranian Broadcasting-linked website Jame Jam. The Fatemiyoun Brigade is made up of Afghan refugees living in Iran.
Three soldiers were also captured by Jabhat al-Nusra, one Afghan member of the Fatemiyoun Brigade and two soldiers of the Syrian Army, Hussein Ali Rezaee, a Revolutionary Guard spokesperson told Fars News agency.
Jabhat al-Nusra published videos and pictures on social media, which appear to show the bodies of Iranian soldiers who had been killed. The group also published photos of soldiers they claim to have captured.
Rezaee asked people not to be affected by the graphic images, which he describes as "psychological warfare."
Tens of Iranian soldiers have been killed in Syria in recent months.
Iran says its soldiers are in Syria to protect holy Shiite shrines and calls the forces "Protectors of the Shrine".
A temporary ceasefire in Aleppo and surrounding areas, which came into place Wednesday at midnight, has been extended for 72 hours, starting Saturday at midnight. Previous ceasefires in Syria have excluded conflicts with Jabhat al-Nusra and the Islamic State.
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