A rebel onslaught on the town of Khan Touman near Aleppo last week delivered one of the biggest battlefield setbacks yet to the coalition of foreign Shiite fighters waging war on behalf of Syrian President Bashar al Assad.

Reports put the death toll among the Iranian, Afghani and Lebanese militiamen as high as 80 in the attack spearheaded by the al-Qaida-linked Nusra Front. At least 17 of the dead were Iranians, seemingly the highest toll in a battle outside the Islamic Republic's borders since the Iran-Iraq war.

"Pray for us, we can't move. There are 83 of us in one room. We're waiting for artillery backup so we can pull back," an Iranian fighter wrote in a WhatsApp message, quoted by state-run Iranian website Jaam-e-Jam. "God willing, we are martyred rather than taken prisoner."