UNITED NATIONS - The United Nations vowed to discipline two officials implicated in a report that detailed conflicts of interest and flawed management in the U.N. oil-for-food program, while the man leading the investigation warned that more revelations were forthcoming.

The interim report, released Thursday, zeroed in on the chief of the oil-for-food program, Benon Sevan, saying Saddam Hussein's regime awarded oil allocations in his name to a trading company between 1998 and 2001.

It said Sevan had "seriously undermined the integrity of the United Nations" and suggested he may have received kickbacks, possibly using an aunt to mask his trail.

Sevan has denied he ever received any money.

Based on the report, Secretary-General Kofi Annan will discipline Sevan and another U.N. official, Joseph Stephanides, who may have "tainted" bidding for an oil-for-food contract, said Mark Malloch Brown, Annan's chief of staff.

The $60 billion oil-for-food program, which ran from December 1996 to November 2003, allowed sanctions-bound Iraq to sell oil to buy humanitarian supplies. But it allegedly became a way for Saddam to curry favor and push to end sanctions - by awarding former government officials, activists, U.N. officials and journalists vouchers for Iraqi oil that could then be resold at a profit.

Allegations that the United Nations itself was enmeshed in corrupt practices in the program led Annan to appoint former Federal Reserve Chairman Paul Volcker to investigate. Several U.S. congressional teams are also looking into it.

Volcker told The Associated Press that the investigation found no "systematic mismanagement" of the oil-for-food program. But he said there were serious problems.

He told AP he hoped that his report, which also detailed investigations into U.N. administrative expenses, internal audits and procurement, will begin to answer serious questions raised by critics of the United Nations.

"There are obviously problems in the institution, and we have identified some of them," he said. "But the end of this should be a reformed and stronger U.N., because I believe - and I know the other committee members believe - that the U.N. has an important role to play. But it cannot be effective if it is under suspicion all of the time."

Volcker's investigators are still probing Annan and his son, Kojo, who had been employed by a Swiss company, Cotecna Inspection SA, which had a U.N. contract to certify deals under the oil-for-food program. Volcker is expected to issue a report on this investigation later this winter.

Investigators are still looking into the actions of the U.N. Security Council, which authorized and monitored the oil-for-food program, as well as the performance of U.N. contractors and the activities of U.N. agencies in the field in Iraq.