U.S. officials decided this year to eventually close the prison, in part because it is located in an area heavily populated by insurgents and their supporters.
The raid Saturday was launched at dusk and appeared to involve at least 40 to 50 men, U.S. officers said.

U.S. soldiers inspect an overturned van on the road to Baghdad's airport following an accident involving a U.S. military convoy, witnesses said. Three people were evacuated.
(Hadi Mizban -- AP)
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The insurgents opened the attack with barrages of 81mm and 120mm mortar rounds, followed by rocket-propelled grenades, the U.S. military said. Arab media reports said some of the projectiles landed inside the prison, causing the injuries among detainees.
At least one rocket-propelled grenade hit a corner watchtower, wounding Marine guards inside. The explosion forced the guard team to abandon the tower, Rudisill said. The heaviest damage was caused by a mortar round that destroyed a refrigerator truck, he said.
Ground fighters among the insurgents advanced only after the mortar and rocket assault had ended and attacked the prison from two directions simultaneously. The smaller of the thrusts was apparently a feint to divert attention from the main attack, Rudisill said, who cited both tactics as evidence of sophisticated planning.
Arab media said the attackers withdrew under covering fire. The U.S. military reported one rebel killed and dozens wounded. Authorities declined to say whether any insurgents had been captured.
Rudisill said the prison's walls were not breached and that no inmates escaped. U.S. forces were able to blow up a vehicle bomb before it reached the prison walls, he said.
Rudisill said he believed there was no evidence that a tractor-mounted bomb that exploded near Abu Ghraib on Monday was meant for the prison, saying the explosion was too far away for prison guards to see.
Special correspondent Naseer Nouri contributed to this report.