The Manhattan district attorney's office has launched a criminal investigation of the former director of the $64 billion U.N. oil-for-food program, according to the district attorney's spokeswoman.

The probe of Benon V. Sevan, a Cypriot who was executive director of the program in Iraq from 1997 to 2003, marks the first time that a top official at the United Nations has faced the prospect of prosecution in connection with abuses of its largest humanitarian operation.

The action comes six months after the U.N.-appointed Independent Inquiry Committee, headed by former Federal Reserve chairman Paul A. Volcker, concluded that Sevan had engaged in a "grave" conflict of interest by steering lucrative oil deals to an Egyptian oil trader. Volcker is continuing his own investigation to determine whether Sevan received payoffs in exchange for the favor.

U.N. Secretary General Kofi Annan indicated though spokesman Stephane Dujarric that he would lift Sevan's diplomatic immunity if formal criminal charges were brought against him. "Should any criminal charges be brought against a U.N. employee in connection with the oil-for-food program investigation, the secretary general is committed to lifting that person's immunity," Dujarric said.

Sevan has denied any wrongdoing.

The oil-for-food program was established in December 1996 and allowed Iraq to sell oil to buy food, medicine and other humanitarian goods. Saddam Hussein's government allegedly received more than $2 billion in illicit kickbacks from companies trading with Iraq.