A senior officer in Iran’s elite Revolutionary Guards unit has been killed in Syria, the fourth Iranian commander to die there in the last month, state media said Tuesday.

Colonel Ezzatollah Soleimani died during an “advisory mission” near the northern Syrian city of Aleppo, according to Fars news agency.

Iranian media have since Saturday announced the deaths of five Iranians in Syria, bringing the total killed there to at least 20 since October 9.

Among those have been four Revolutionary Guards commanders, including General Hossein Hamedani, a veteran of the Iran-Iraq war, who was killed by the Islamic State (ISIS) jihadist group near Aleppo.

Two other senior officers were killed less than a week later.

Iran supports the regime of Syrian President Bashar al-Assad, and while it doesn’t officially acknowledge sending troops to Syria, it has admitted to deploying military “advisers” to the war-torn country.

AFP contributed to this report.