Even when they are between missions, US special forces dubbed the "green berets" are never far from Afghanistan where they have been fighting for almost eight years.

Unlike other troops, they are highly trained to operate in elite 12-strong autonomous units mostly behind enemy lines, and they usually return time and again to the same regions of Afghanistan relying on a network of carefully cultivated local contacts.

Even during their down time in the United States at the sprawling Fort Bragg military complex in North Carolina, training remains intense and not just to maintain a top-notch level of physical fitness.

Here they have to learn some of the foreign languages spoken on the ground -- Pashtun, Dari and even some Arabic.

And they train with Afghan interpretors, employed by the US Army here, to gain a better understanding of local customs and cultures.

"They are much better prepared for what they are going to encounter than other soldiers," said Colonel Francis Beaudette, chief of staff of the special forces based at Fort Bragg, during a rare visit by a handful of journalists.