The Pentagon has begun putting into place a new program under which hundreds of prisoners being held by the US military in Afghanistan will be given the right to challenge their detentions, a defense official said Sunday. Prisoners at the Bagram military base are all to be given a US military official to serve as their personal representative and a chance to go before new so-called Detainee Review Boards, to have their cases considered, said the official, who spoke on condition of anonymity to be able to discuss a program that has not been formally announced. The initiative amounts to the first time prisoners will be able to call witnesses and submit evidence in their defense. There are some 600 detainees at the facility, some who have been held for up to six years. An order creating the review boards was signed in July by Deputy Defense Secretary William Lynn. Some military officers serving in Afghanistan have already been assigned to the boards and some who will serve as personal representatives have already been identified, the official said. He declined to say whether any proceedings have already been held. The guidelines came to light as the Obama administration is reviewing Bush-era detention policies and determining where to make changes. The proposed rules were given to Congress in mid-July for a 60-day review, according to The Washington Post and New York Times, which reported on the new program in stories late Saturday night on the Web. Under the rules, the military-assigned representatives, though not lawyers, are charged with gathering evidence and calling witnesses on behalf of the prisoners. That process is similar to the one used for detainees at the US military prison at Guantanamo Bay, Cuba. Unlike those prisoners, the Bagram detainees have had no means to challenge their detentions or to hear allegations against them. But the official said the initiative is more like a system used in Iraq than in Guantanamo.