At least 1,000 Iranian soldiers deployed to Syria have been reportedly killed, an Iranian official said, underlining Tehran’s increasing presence on front lines of the Syrian conflict.

Iran has been sending countless troops to back authoritarian Bashar al-Assad in the Syrian civil war.

The recently pronounced death toll has taken a major hike compared to figures accounted for just four months ago– Iran had only recognized 400 of its soldiers dying on Syria’s battlefields.

Iran has been sending fighters to Syria since the early stages of the more than five-year-old war to support its ally, Assad, against Syrian rebels trying to topple him. The Tehran regime had viewed its activity in Syria as a step taken further towards its expansionist plans for the region.

Although many of the soldiers Iran sends are its own nationals, it is casting its recruitment net wide, training and deploying from neighboring Afghanistan and Pakistan as well. Half of the death toll reported in August were Afghan citizens.

“Now the number of Iran’s martyrs as defenders of shrine has exceeded 1,000,” Mohammadali Shahidi Mahallati, head of Iran’s Foundation of Martyrs, which offers financial support to the relatives of those killed fighting for Iran, was quoted as saying by Tasnim news agency.

Iran alludes to its fighters in Syria as “defenders of the shrine”, a reference to the Sayeda Zeinab mosque near Damascus, as well as other shrines revered by Shi’ites.

Many Iranians initially opposed involvement in Syria’s war, harboring little sympathy for Assad

With public opinion swinging increasingly behind the cause, numbers of volunteer fighters have soared far beyond what Tehran is prepared to deploy in Syria.