Washington: The State Department is unable to account for the $1.2 billion it gave to security firm DynCorp International to train Iraqi police, according to a government report on Tuesday.

"The bottom line is that State can't account for where it went," said Glenn Furbish, who contributed to the 20-page report for the Office of the Special Inspector General for Iraq Reconstruction.

The report said that Bureau of International Narcotics and Law Enforment Affairs (INL) "had not validated the accuracy" of invoices received prior to last October, and that the lack of controls "created an environment vulnerable to waste and fraud".

"Bills came in; they paid the bills, but they don't know what they paid for and they don't know what they've gotten," said Furbish, an accountant by training who spent two years in Iraq.

"It's like so much else that happened in Baghdad ... there was just a massive quantity of work and too few people in place to do it. They just essentially did not have the staff to monitor what was going on,'' he said.

As a result, the audit agency announced it has suspended its oversight of the agency's project until the INL gathers the information.

The report coincides with a controversy over the use of private security firms in Iraq, particularly Blackwater USA, which is under scrutiny over a September 16 shooting incident in Baghdad in which 17 people were killed.

The Pentagon and the State Department are employing more than 7,000 security contractors in Iraq. US officials say they are needed to free up soldiers for other tasks.