By Mark Gregory
BBC World Service business correspondent
A United Nations panel has found that the US-led occupation authority failed to exercise proper controls over Iraq's oil industry and could not say how much oil had gone missing since the fall of Saddam Hussein.
The panel said US-led authorities failed to deal with widespread oil smuggling
The International Advisory and Monitoring Board report also said there were "important weaknesses" in the management by occupation officials of up to $20bn in Iraqi funds, mostly from oil sales.
US politicians have often accused the UN of incompetence and, perhaps, corruption in its handling of the oil-for-food programme, a scheme to alleviate Iraqi suffering under sanctions before the war. Now the boot is on the other foot.
The panel, which also includes representatives from the IMF and the World Bank, expressed particular concern about how large contracts paid out of Iraqi funds were given to US firms, such as the oil services group Halliburton, without competitive bidding.
Other problems identified included weaknesses in administration, inadequate accounting systems, poor record-keeping and a failure to follow procedures that had been agreed.
The panel's report says the US-led authorities also failed to deal with widespread smuggling of Iraqi oil out of the country immediately after the war. Nobody knows how much revenue for reconstruction was lost as a result.
It also says there were inadequate controls to prevent the misuse or theft of funds at Iraqi government ministries.