The US government, which is spending $4bn a month keeping its troops in Iraq, admitted yesterday that the cost had risen rapidly, and that the price of reconstruction was "almost impossible to exaggerate".

In an interview with the Washington Post, the head of the occupation authority, Paul Bremer, said it would require a huge undertaking and countless billions to rebuild the infrastructure and economy. It is estimated that it will cost $2bn to meet the current demand for electricity, and $16bn to deliver drinking water.

Ramiro Lopes da Silva, the interim head of the UN mission in Iraq, said last week's attack on the UN headquarters in Baghdad had stalled the reconstruction of Iraq and would prolong the occupation.

Mr Lopes da Silva, appointed after Sergio Vieira de Mello was killed in the attack, said lack of security would limit the UN's work and deter others from joining efforts to rebuild postwar Iraq.

"Even private contractors, companies that were intending to operate in Iraq, are now going to have to reassess the levels of threat before they take their next steps," he said.

Meanwhile, a military tribunal has begun hearing the case against four US army reservists who allegedly abused Iraqi prisoners of war by kicking and punching them in the groin, face and abdomen.

The four, members of 320 Military Police Battalion, were part of a unit taking a busload of captives to Camp Bucca in the port of Umm Qasr, where prisoners of war are processed.

The offenses they may be charged with include assault, maltreatment of prisoners and dereliction of duty.

One prisoner is alleged to have had his nose broken and another his wrist injured. Others were allegedly held down while fellow prisoners were encouraged to kick them.

The soldiers claim that they acted in self-defense.

The case has caused an uproar in the soldiers' home state, Pennsylvania. "A bloody nose and a twisted arm, and our kids are facing prison time?" said Linda Edmondson, the mother of one of the four, Sergeant Shawna Edmondson.

"In time of war, its ridiculous. She could have shot them if she wanted to hurt someone."

Elsewhere in Iraq, two US soldiers were killed in guerrilla attacks yesterday in Falluja and Baghdad.

© Guardian Newspapers Limited 2003

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