The video obtained by CNN shows the injured Afghan man being pulled from the rubble of the building by anti-Assad Islamist fighters.
The man confesses to his interrogators that he was recruited by Iranians to fight in Syria and was receiving $500 in monthly salary.
Identified as Sayed Ahmad Hussaini, the man says he was trained and then sent to assist the regime in Syria and defend the Zainab shrine.
The frustrated man says he does not want to fight anymore and want to go home.
At least 3,000 Afghan nationals have reportedly been deployed to take part in the ongoing Syria conflict, according to informed government sources.
The Afghan militants are fighting fighting on both sides of the Syrian war, in support of the Syria Bashar al-Assad and the Islamic State of Iraq and Syria (ISIS) militants.