A retired Iranian general has been killed while battling jihadists as a volunteer in northern Syria, Iranian media reported on Wednesday.

Ahmad Gholami, who had served as a senior Revolutionary Guards commander in the Iraq-Iran war of the 1980s, died on Tuesday "while fighting the takfiri terrorists in Aleppo, Syria," said the Fars news agency, which is close to the Guards.

Iran uses the term "takfiri" to describe Sunni jihadists.

Gholami went to Iraq and Syria "voluntarily" to fight Islamic State group jihadists, it added.

Iran is the principle backer of President Bashar al-Assad. It denies that any of its professional soldiers are active in Syria -- insisting its commanders and generals act purely as "military advisers" -- but it also leads large volunteer forces, comprised of fighters from both Iran and neighbouring Afghanistan.

Iran does not provide precise casualty figures for those killed in action in Syria and Iraq, but Iranian media have previously reported "hundreds" of military advisers and volunteers have died in recent years.