An expert panel called...for more transparency surrounding the deepening reliance of the United Nations on private security companies for services from armed guards to police training. The Working Group on the Use of Mercenaries...held a series of meetings and debates...as part of its ongoing investigation into a practice that is drawing increasing scrutiny...Some academics and U.N. member countries worry that the United Nations is compromising its legitimacy by involving such firms in its peacekeeping and peace building operations...While the U.N. has taken steps to clarify its policies, panel members said many issues remain unresolved. Among those is how to hold contractors accountable for abuses committed in the field and the establishment of an oversight mechanism to ensure compliance with international standards...U.N. officials say the reliance on private security firms is reflection of an increasingly dangerous world for United Nations workers. [refers to DynCorp]