The attack was part of a pattern of insurgent attacks on the prison, west of Baghdad.
American forces took over the prison, just west of Baghdad, which was notorious during the Saddam Hussein government.
Five people, including one woman, were killed when a missile fell on their houses in a populated district in the west of Baghdad.
Then the inspectors would fly to Habbaniya, an airfield west of Baghdad.
At a news conference in Falluja, west of Baghdad, he said that two dozen men of military age were among those killed.
American forces are only now venturing west and north of Baghdad in substantial numbers.
Hard-line Islamists dominate several cities just north and west of Baghdad.
Iraq has placed Al Samoud missiles north and west of Baghdad.
In a separate incident, a roadside bomb just west of Baghdad killed another soldier on Monday night, the military said.
The prison, west of Baghdad, is a nucleus of despair.