The basij volunteers became national heroes during the 1980-1988 war of attrition against Iraq. More recently, they have been employed to put down student demonstrations and crack down on women who flout strict dress codes.

In Teheran, some 3,000 basij, clutching automatic rifles and wearing chequered headscarves, paraded before President Mahmoud Ahmadinejad and chanted “God is the Greatest”.

Ahmadinejad told them their militia spirit would help thwart foreign powers in an international dispute over Iran’s atomic ambitions.

“Of course the (foreign powers) get angry when they see the power and spirit of the militia now governs our international policy, diplomatic relations and negotiations,” the president said. “In reply to their anger say: Go ahead, be angry but Die in your anger.”