The US Corps of Engineers built the 27-million-dollar facility at Chamchamal in the autonomous Kurdish region, 70 kilometres (43 miles) south of Sulaimaniyah, in the space of two years.

It was constructed on the site of a federal jail that had existed under the regime of executed dictator Saddam Hussein, the statement said.

Engineers had to redesign the existing facility "to make it a modern correctional facility that complies with both international and US Coalition requirements for the humane treatment of inmates," it said.

The new jail was constructed to hold 2,000 medium security inmates and 1,000 high security inmates and will have a staff of 1,200, including a large force of guards.

There is already another federal prison, Fort Suze, 20 kilometres northwest of Sulaimaniyah, housing 1,500 detainees, among them 260 foreigners. Most inmates there are accused of "terrorism" and illegal entry to Iraq.