Fights involving water bottles filled with sand or rocks being thrown and tent stakes wielded as spears have erupted regularly, a US psychological operations officer, Major Joel Droba, said.

But he added that, so far, the riots have only pitted groups of Iraqis against others, rather than targeting the coalition military policewatching them.

"Some of it had to do with Shiites being together with Sunnis and not getting on. We had to separate them," he said, referring to the two main streams of Islam.

Camp Freddy, as the detention camp in southern Iraq is known, has grown markedly since it was established in the opening days of the war by British military engineers.

The heavily guarded area of desert enclosed by razor wire and sand barriers still has the big white tents used as temporary "pens", but now the prisoners are being transferred to two new semi-permanent facilities in the compound.

Outside, a crowd of Iraqis looking for relatives are kept to one side. A female US soldier took their details and information about their loved ones, entering it into a computer for the use of camp commanders and the International Committee of the Red Cross (ICRC).

Inside, visitors were kept well away from the prisoners. Journalists did see three Iraqi detainees waiting outside the hospital area, two of them sitting quietly on the sand while the other lay on his side.

Initially, those brought to the camp were captured by or surrendered to British forces in southeast Iraq, but with US forces pushing past Baghdad and taking control of much of the country, many of the new arrivals have come in under US responsibility.

All are being treated strictly in accordance with the Geneva Conventions, a senior US MP, Captain Lisa Weidenbush, said.

ICRC inspectors, she claimed, "are very pleased with the humane treatment of our prisoners."

All are provided with blankets and a box of food and hygiene products, and undergo medical screening, she said.

Those men -- there are no women among the detainees -- who can prove that they are civilians are transported back to their communities and released.

The others are sorted into one of two categories: Enemy Prisoner of War (EPW) or unlawful combatant. The first comprises soldiers who fought in uniform, while the latter covers all others -- including the notorious Saddam Fedayeen paramilitary force and armed Baath party members.

One US officer from the military legal unit who declined to give his name admitted that the decisions to hold prisoners often stemmed from circumstantial clues, such as individuals found to be carrying large sums of money, or "civilians" wearing military boots.

Nevertheless, he said he was surprised at the relatively low number of prisoners.

Under the Geneva Conventions, prisoners of war have to be released once a conflict is over.

He said that could only be determined by US Defense Secretary Donald Rumsfeld.

But he added "I don't think it will be the same situation" as the US "war on terrorism" in Afghanistan since October 2001. That campaign has resulted in hundreds of detainees being held indefinitely at a US base in Cuba outside normal Geneva Convention guidelines.

SPACE.WIRE