Almost 700 Iranian soldiers and militia fighters have been killed in Syria’s civil war, laying bare the scale and cost of Tehran’s intervention to preserve Bashar al-Assad’s grip on power.

Officially, Iran maintains that only “military advisers” have been deployed in Syria. But the state media has reported numerous battlefield casualties, with the Islamic Revolutionary Guard Corps (IRGC) disclosing last week that 13 of its fighters were killed near Aleppo.

About 2,000 troops from the Quds Force - the special forces wing of the IRGC - are present in Syria, according to the International Institute for Strategic Studies (IISS). In addition, 13 Shia militias have been identified among the forces fighting for Assad’s regime.

The IRGC provides these units with recruits, weapons, training and military planning. In total, at least 3,000 Iranian military personnel are believed to be in Syria.