A group led by al-Qaida ally in Iraq Abu Mussab al-Zarqawi claimed on Sunday responsibility for a bold attack that left 44 US soldiers injured, according to a website statement.
"Your brothers in the Organization of Al-Qaida in the Land of Two Rivers mounted a planned attack on Abu Ghuraib prison, where Muslim men and women are held," the statement said.
Car bombs were detonated and rocket propelled grenades were fired, an attack followed by an overnight gun battle around the base taken by "infidel forces," it added.
The group said it would provide a footage about the attack. The statement could not be verified.
The US military said between 40 to 60 insurgents were involved in the assault, which wounded 44 soldiers and 12 detainees, but the prison was secured and locked.
Most of the injuries were light, but several were serious, the US military said.
The attack was the latest and the most fierce attack targeting the Abu Ghuraib detention center, taken by the US-led multinational forces as a forward base.
It was unknown if any of the insurgents were arrested or suffered casualties.
Insurgents have previously shelled the prison, where prisoners were abused by US captors. The notorious detention center, 20 km west of Baghdad, holds more than 3,000 detainees.