WASHINGTON (AP) - Congressional investigators said Thursday that Saddam Hussein's government reaped $10.1 billion in illegal revenues related to the United Nations' oil-for-food program - much more than previous estimates.

A U.N. Security Council resolution requires member nations to freeze accounts and financial assets that might hold Iraqi money and transfer the funds to Development Fund for Iraq. The members of Saddam's family on the Treasury list were "critical to the financial workings and underpinnings of the regime," Treasury official Juan Zarate told a House panel.

The oil-for-food program allowed Saddam's government to sell oil if the money was used to buy humanitarian goods and pay victims of the 1991 Gulf War. Other oil sales were prohibited under a U.N. embargo imposed after Iraq invaded Kuwait. The program ended in November.

The GAO had previously estimated that Saddam's government had received $6.6 billion in illegal revenues from the program from 1997 through 2002.

But using updated data, the GAO has concluded that Saddam received $5.7 billion from oil smuggled out of Iraq and $4.4 billion in illicit surcharges on oil sales and purchases of commodities, according to testimony prepared for the House Financial Services oversight and investigations subcommittee.

On Wednesday, U.N. spokesman Fred Eckhard said the United Nations had asked the U.S.-appointed Iraqi Governing Council and U.S.-led coalition to provide evidence of the corruption. The request followed reports that former Cabinet officials, legislators, activists and journalists had profited from Iraqi oil sales.

In its testimony, the GAO said the United States has had mixed results in recovering Saddam's hidden assets. The United States has seized about $926 million of the assets of Saddam's regime in Iraq and other countries have frozen about $3.7 billion of Iraqi regime assets. But little progress has been made in identifying and freezing most of Saddam's hidden assets. GAO said the regime was believed to have illegally acquired $10 billion to $40 billion.

But Zarate, the Treasury Department's deputy assistant secretary for terrorist financing and financial crimes, told the House Financial Services Subcommittee on Oversight and Investigations that the program has had recent successes.

Almost $2 billion of Iraqi assets has been newly identified and frozen outside the U.S. and Iraq within the last year. About $750 million has been transferred to the Development Fund for Iraq, controlled by the Coalition Provisional Authority.

"One of the conundrums of this effort has been trying to understand and get a hold on the full universe of assets pilfered by the Hussein regime," Zarate said.