The United Nations is under increasing pressure to ensure the availability to investigators of documents on which Volcker Committee based its findings on alleged involvement of individuals and companies from dozens of countries, including India, in the massive corruption in Iraq's oil-for-food programme.

Diplomats and officials feel that the documents may be destroyed if the idea of Volcker Committee to return the papers obtained on the basis of confidentiality from concerned countries or entities was implemented.

A statement from the committee said all material will remain under its control, and it is 'making arrangements with the United Nations for the appropriate and orderly availability and disposition of committee materials'.

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The failure to reach an agreement on the handling of records has led to extension of the operation of the Volcker Committee by one month till December 31 at the cost of hundreds of thousands of dollars.

In a letter to UN Secretary General Kofi Annan, US Ambassador John Bolton has asked him to direct the Independent Inquiry Committee which just completed its probe into the $64 billion programme 'to preserve the integrity of the files' so law enforcement officials can pursue criminal cases against companies and individuals named in the report.

The US is concerned that if the files are returned to the countries, that provided them to the investigators on the basis of confidentiality, they could disappear, which could make the prosecution of corrupt officials and companies difficult, he said.

"The purpose of our letter is to underscore the importance of not distributing the documents back to their original sources," Bolton said, adding, "If we can keep the documents together, it's a real basis for further investigation. We don't want to see these documents going into paper shredders around the world."

The allegations against former External Affairs Minister K Natwar Singh and the Congress as also Indian companies were apparently based on the documents supplied by Iraq.

Bolton has also proposed that Annan and the Security Council work with Iraq to use the oil-for-food money to keep the Committee operational for the limited purpose of maintaining 'integrity and accessibility' of documents.

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A UN spokesperson said on Wednesday that the discussions among the world body, the Committee and Iraq on the issue were continuing. The Committee is said to have received thousands of documents from Iraq on the understanding that the confidentiality would be maintained.

Officials and diplomats said several countries might like to investigate their companies and other 'non-contractual' beneficiaries and some provision needs to be made that the documents are available at a central point. The investigations could take months to complete and, therefore, it is necessary to ensure that they are not lost.