More than 2,000 Afghans deployed by Iran have been killed fighting in Syria on the side of President Bashar al-Assad's regime, an official in the volunteer force told Iranian media.

The Fatemiyoun Brigade of Afghan "volunteer" recruits has been fighting in Syria for five years, said Zohair Mojahed, a cultural official in the brigade.

"This brigade has given more than 2,000 martyrs and 8,000 wounded for Islam," he said in an interview with the reformist Shargh newspaper published Saturday.

Iran rarely provides figures on the numbers fighting and killed in its operations in Syria and Iraq.

The last toll was provided by the veterans organisation in March, which said 2,100 volunteers had died without specifying how many were foreign recruits.

Iran denies sending professional troops to fight in the region, saying it has only provided military advisors and organised brigades made up of volunteers from Iran, Afghanistan and Pakistan.

The Fatemiyoun is reportedly the biggest military unit deployed by Iran in Iraq and Syria, made up of recruits from Afghanistan's Shiite minority.

Iran has backed Afghan forces in the past against the Taliban in their own country, as well as mobilising them against Saddam Hussein's forces in the Iran-Iraq war of 1980-88.

Some 3,000 Afghans died fighting Iraq in the 1980s, Mojahed said.

Tehran offers Iranian citizenship to the families of those foreign fighters "martyred" in the conflicts of Syria and Iraq.

Iranian media has reported on the funerals of volunteer "martyrs" and aired television features about their presence in Syria.

Source: AFP