Updated

Syria had a more than $3 billion role in funneling money and weapons to Saddam Hussein during the period of the scandal-plagued U.N. Oil-for-Food (search) program, according to documents obtained by the House International Relations Committee.

The documents, prepared by IRS special agents, have emerged as a new avenue in Congress' investigation into Oil-for-Food. Congressional investigators on Wednesday will hold a 10:30 a.m. EDT hearing to probe the actions of Syria and President Bashar Assad (search).

The papers expose how Syria was used by Saddam as a major conduit for illegal oil exports and weapons deals, effectively short circuiting the humanitarian intent of Oil-for-Food. At the same time, Damascus profited enormously from the relationship which included laundering money for Saddam and, after the U.S. invasion of Iraq in 2003, funneling hundreds of millions in Iraqi money out of that government's hands without authorization.

At least some of that money could be fueling terrorist attacks against U.S. forces based in Iraq, investigators believe.

Click here to read the documents released by the House International Relations Committee (pdf file).

Following the collapse of Saddam Hussein's (search) government in 2003, IRS criminal investigators opened an inquiry into Iraqi operations of Oil-for-Food and interviewed numerous mid-level government officials, former Iraqi ministers and other imprisoned officials and supplied information to Congress, CIA and IRS.

Commercial transactions and deposits were uncovered that implicated the Syrian government in the Oil-for-Food scandal.

The IRS learned through its interviews that Iraq's State Oil Marketing Organization (SOMO) maintained accounts at the Commercial Bank of Syria (CBS) that received funds from the oil sales to Syria. Beginning in June 2000 and lasting until March 2003, Iraq and Syria set up a border trade protocol, which ultimately resulted in $3 billion worth of Iraqi oil being imported by Syria.

IRS investigators have concluded that the money was funneled through these accounts. About 40 percent was paid in cash while the other 60 percent came in "goods" such as arms.

Both the imports of oil and the exports of military supplies were illegal under U.N. sanctions imposed after the first Gulf War.

Funds in these accounts were used to purchase merchandise through Syrian suppliers, transferred in cash to Baghdad using a diplomatic courier, and used to pay the 10 percent kickback demanded by Iraq of all companies involved in the U.N. program, according to the House International Relations Committee.

And some of the highest officials in the Syrian government were part of the illegal trade, according to the probe.

IRS investigators have also determined that Syrian Defense Minister Mustapha Tlas (search) received a "tribute payment" in return for permitting trade between the two countries in violation of U.N. sanctions. Tlas' son, Firas, and other officials with personal ties to Assad, also received commissions for acting as intermediaries in military procurement contracts. Another intermediary was Thualhima Shaleesh (search), chief of the presidential bodyguard and cousin of the Syrian president.

One document details how Iraq's Military Industrialization Commission (search) used intermediaries to arrange for arms imports. Another document says that a source at the Iraqi Ministry of Trade (search) told the U.S. agents, "the majority of the Iraqi trade with Syria was transacted through [a company called] SEAS ... belonging to Dr Asef Shaleesh. He mentioned that Shaleesh was related to the president of Syria."

The Bush White House and previous administrations have known that Syria was violating the sanctions and importing enormous amounts of oil illegally from Iraq. In fact, one of former Secretary of State Colin Powell's first trips was to the Middle East, including a stop in Syria, to urge Iraq's neighbors to strengthen the sanctions against Saddam.

At that point, the United States was still somewhat hopeful that the younger Assad would be a more flexible and democratic leader than his father

"Candidly, we then discussed the Iraqi-Syrian pipeline. Of course, as you know, the Syrians want to stay within the context of the U.N. Security Council resolutions to play their role and they have been on record with that," Powell told reporters after his meeting with Assad on Feb. 26, 2001.

"The president said to me in response to my query that it is their plan to bring that pipeline, and what is going through that pipeline and the revenues generated in that pipeline, to be under the same kind of control as other elements of the sanctions regime. I found that to be a very important statement on his part, and we have passed that information to President Bush; he has been informed of that, and he also was pleased."

As for what happened to the billions of dollars in cash, IRS agents cannot say for sure; some of it has been traced, some of the Iraqi accounts in Syria are frozen, but possibly hundreds of millions of dollars were taken out of those Syrian accounts and transferred to banks in Beirut, Lebanon.

After the transfers, investigators say "a special truck would be dispatched to withdraw the money and bring it to the Central Bank of Iraq. These trucks would make the journey at least on a weekly basis."

On Wednesday, the hearing by the House International Relations Joint Oversight Subcommittee will feature witnesses such as: Elizabeth Dibble, deputy assistant secretary for the State Department's Bureau of Near Eastern Affairs; Dwight Sparlin, director of operations, policy and support for the criminal investigations division of the IRS; and Victor Comras, former member of the U.N. Al Qaeda monitoring group.

FOX News' Jonathan Hunt and Teri Schultz contributed to this report.