It is feared security contractors may put aid workers at risk
Thirteen Democratic senators have requested US Defence Secretary Donald Rumsfeld provide more information and lay down rules for private security contractors working in Iraq.
The issue of private foreign security firms in the country has received increased attention since four men working for North Carolina-based Blackwater USA were killed nearly two weeks ago in Fallujah, a centre of guerilla activity about 48km west of Baghdad.
There are more than 10,000 foreign security contractors on the ground in Iraq, assigned to tasks ranging from protecting Paul Bremer, the head of the US-led Coalition Provisional Authority to guarding food shipments.
'It would be a dangerous precedent if the United States allowed the presence of private armies operating outside the control of governmental authority and beholden only to those who pay them,' read the letter sent by the senators. 'In the context of Iraq, unless these forces are properly screened by United States authorities and are required to operate under clear guidelines and appropriate supervision, their presence will contribute to Iraqi resentment.'
With no uniforms , there is concern, especially among foreign civilians in Baghdad, that private security personnel sometimes blur the distinction between aid workers and the military.