The commanders said they had learned to mount complex ambushes and lay improvised explosive devices (IEDs).
The accounts of two commanders, in interviews with The Sunday Times, are the first descriptions of training of the Taliban in Iran.
According to the commanders, Iranian officials paid them to attend three-month courses during the winter.
They were smuggled across the border to the city of Zahidan, in southeast Iran, an hour’s drive from training camps in the desert.
Instructors in plain clothes provided daily exercises in live firing. The first month was devoted largely to teaching the Taliban how to attack convoys and how to escape before NATO forces could respond.
During their second month they were shown how to plant IEDs in sequence so that the rescuers of soldiers wounded in one blast would be caught in further explosions.