A report from a committee of the US Senate has claimed that two foreign politicians, British MP George Galloway and former French government minister Charles Pasqua were given allocations of oil by Iraq under the UN's oil-for food-programme.
Now a second report has extended the claims to include senior Russian officials. BBC News examines the background to the accusations.
Q: What was the oil-for-food programme?
The oil-for-food (OFF) programme was a $60bn (£32bn) scheme set up in 1996 by the United Nations that was supposed to allow Iraq to buy food, medicine and other humanitarian supplies with the proceeds of regulated oil sales, without breaking the sanctions imposed on it after its 1990 invasion of Kuwait.
The programme aimed to relieve the suffering of ordinary Iraqis under the sanctions and was formally ended in 2003 after the US-led invasion of Iraq and the overthrow of Saddam Hussein.
Q: What is the scandal?
The scandal emerged in early 2004, after an Iraqi newspaper published a list of about 270 people including UN officials, politicians and companies it alleged may have profited from the sale of Iraqi oil during the OFF programme. Mr Galloway and Mr Pasqua were on that list.
Later, US Senate investigators concluded that the Iraqi regime under Saddam Hussein made $17.3bn from abuses. About $13.6bn allegedly came from selling oil to neighbouring states keen to breach the sanctions.
A further $4.4bn was allegedly earned through kickbacks and illegal surcharges on services and goods provided by companies contracted under the OFF programme, the Senate investigators found.
The UN has also come under fire as the organisation responsible for administering the OFF programme.
Q: What are the new allegations?
The report from the Subcommittee on Investigations of the Committee on Homeland Security and Governmental Affairs presents what it says is evidence "establishing that Charles Pasqua, the former French Minister of the Interior and George Galloway, a newly re-elected Member of the British Parliament, were granted substantial oil allocations from the Hussein regime under the UN Oil for Food Programme".
The significance of someone being given "allocations" is that, under the UN oil-for-food project, Iraq was allowed to sell oil in exchange for food and medicines. It often allocated oil to favoured individuals and companies who could then charge a commission for selling the oil on.
On 16 May, a second set of reports accused Russian politician Vladimir Zhirinovsky, and former presidential aides Alexander Voloshin and Sergei Issakov, of receiving allocations.
The new reports cited documents alleging that Mr Zhirinovsky and Mr Issakov directly requested or negotiated for oil allocations, and that all used a US oil firm - Bayoil, some of whose representatives have been indicted by the US - as an intermediary.
But none of the committee's evidence suggests direct contacts between the three Russians and the Saddam Hussein regime over oil. Nor does the committee present evidence that any of the five men actually received any financial gain.
Q: What is the allegation against George Galloway?
The report claims that "the Hussein regime granted Galloway six oil allocations totalling 20 million barrels of oil, starting in Phase VII of the program (2000) and continuing through Phase XIII (2003)".
The report states that, for each of these allocations, the evidence indicated that Iraq "contracted with one of two entities - Aredio-Petroleum France or Middle East Advanced Semiconductor, Inc. ("Middle East ASI"). The president of Middle East ASI was Fawaz Zureikat, who facilitated several oil transactions for George Galloway."
The report also claims: "Galloway appeared to use a charity for children's leukaemia to facilitate at least one of his oil transactions."
Mr Galloway is due to testify before the committee on 17 May.
Q: Who is Fawaz Zureikat and what is the children's charity?
Fawaz Zureikat is a Jordanian businessman who is said to be an associate of Mr Galloway. He has previously strongly denied making any arrangements linked to oil sales on behalf of Mr Galloway.
The children's charity mentioned is the Mariam Appeal. Mr Galloway set this up in 1998 to provide treatment for Iraqi children, including a four-year-old girl named Mariam Hamze who had leukaemia, and to publicise the plight of such children.
The report notes that £1m was raised by the appeal, with half the money said to be from the United Arab Emirates and the other half from Fawaz Zureikat. Mr Galloway is quoted as saying that no money came from Iraq.
The report claims that a document from the Iraqi oil ministry "indicated that the oil had been allocated to 'Mariam's Appeal'... This document indicates that Galloway may have used the charitable organisation to conceal payments from the oil allocation".
The appeal was investigated by the British Charity Commission in April 2003. It found some technical violations (the appeal should have been registered as a charity immediately, for example) but took no further action.
It named Mr Zureikat as the chairman of the appeal from 2001 and reported that he had taken the appeal's books to Amman and Baghdad.
Q: What evidence does the US subcommittee rely on?
The committee says that it has found documents in the Iraqi oil ministry listing contracts in the oil-for-food programme. It has also interviewed senior Iraqi officials including former Vice-President Taha Yassin Ramadan and former Deputy Prime Minister Tariq Aziz, both of whom were questioned by the committee in April 2005.
Mr Ramadan, it says, told the committee: "Galloway had been granted oil allocations 'because of his opinions about Iraq' and because Galloway 'want[ed] to lift the embargo against Iraq'. " Another official is quoted as saying that "George Galloway was the owner of a company that was involved in the Iraq oil trade scheme."
Q: Was George Galloway cleared in a British libel case?
Yes, he won a case against the Daily Telegraph in December 2004. The Telegraph found documents in the Iraqi foreign ministry after the fall of Saddam Hussein that appeared to show that Mr Galloway had received money from the Iraqi government and wanted some more. He strongly denied this.
He won the case after the judge ruled that he had been seriously defamed as the paper had conveyed to fair-minded readers that he had been in the pay of Saddam Hussein. He had not been given an adequate opportunity to respond.
The Senate subcommittee says that its documents - from the oil ministry - are different, and came later, from the one in the Telegraph case, which was found in the foreign ministry.
Q: What is Mr Galloway's reply?
George Galloway has dismissed the Senate subcommittee report. "This cannot possibly be called an investigation," he stated.
"This is a lickspittle Republican committee, acting on the wishes of George W Bush," he said.
He denied that he had ever owned a company as claimed in the report and also denied that he had benefited in any way from the oil-for-food programme.
Q: What about Mr Pasqua?
The report says that the subcommittee "has uncovered evidence that the Hussein regime granted allocations of 11 million barrels of oil to Charles Pasqua. The evidence includes internal documents of the Iraqi ministry of oil created during the regime of Saddam Hussein.
"In addition, senior Hussein regime officials that were interviewed by this subcommittee confirmed that Iraq granted oil allocations under the oil-for-food programme to Charles Pasqua."
Mr Pasqua has also denied the charges. "I have never received anything from Saddam Hussein," he is quoted by the report has saying.
In a separate statement, he said the report was based largely on earlier accusations that he "strenuously denied" in January 2004 and October 2004.
The report also repeats allegations first printed in the UK Financial Times newspaper and Italy's Il Solo 24 Oro, Mr Pasqua said. He is suing both publications for defamation.