Eight Iranian fighters have been buried in Iran Thursday after they were killed fighting ISIS in Syria, according to Iranian state media.

Three of the men, all of whom were described as “volunteers,” were buried in the capital Tehran, while the others were buried in the northeastern city of Mashhad, according to the official IRNA news agency.

Thousands of people attended the funerals, it said.

Another Iranian state media outlet, Tasnim, published pictures of the men in civilian clothing. Neither outlet gave any indication of their rank or with what specific force they were fighting with.

Iran is the main backer of the regime of Bashar al-Assad in Syria, supplying his embattled forces with weapons and equipment, and training and equipping numerous loyalist militias – including Hezbollah – to supplement the badly-overstretched Syrian national army.

However, though it admits to sending “military advisers,” Tehran denies it is deploying combat troops on the ground – despite the steady stream of evidence, including a mounting body county.

As that role has become harder to deny, the Iranian regime has been attempting to explain the presence of Iranian fighters on the ground by encouraging “volunteers” from its various military and paramilitary forces to travel to fight in Syria and Iraq – all while still denying the government is actually sending fighters itself.