A conservative anti-corruption group has filed a lawsuit against the State Department, accusing the agency of illegally withholding documents that could shed light on the scandal involving the U.N.-run oil-for-food program in Iraq.

The group, Judicial Watch, filed a request in November under the Freedom of Information Act seeking audits, contracts, and other records about the program, which was intended to relieve suffering in Iraq but allegedly became a haven for cronyism, bribery, and kickbacks.

The president of Judicial Watch, Thomas Fitton, said yesterday that he was stunned when the State Department wrote back that it could not respond to the request until it received the “concurrence” of the U.N.

“Since when does the United States government let Kofi Annan and the U.N. decide what U.S. government documents are made available to the American people?” Mr. Fitton asked. “The conclusion that can be drawn is that the State Department’s covering for the U.N. There are many in the State Department who are sympathetic to that body,” he said.

“It goes to the old saw, that’s completely appropriate here, that ‘We need an American desk at the State Department,'” Mr. Fitton said.

The United Nations’ $64 billion oil-for-food program was designed to allow the former Iraqi government to sell limited amounts of oil in exchange for humanitarian goods under an exemption from sanctions in place since 1991.

A spokesman for the State Department, Damon Terrill, said he could not answer questions about the document dispute because his agency had not yet been served with a copy of the lawsuit. “This is the first we’ve heard of it, but we are looking into it,” he said.

Mr. Fitton described the department’s deference to the U.N. as unprecedented, but sources well-versed on secrecy issues said it is not the first time the government has made such an assertion.

However, an attorney with a nonprofit group in Washington that collects declassified government documents, the National Security Archive, said it was odd to see the Bush administration standing up for the U.N.’s authority to keep details of the oil-for-food scandal under wraps.

“It is kind of an interesting thing. They’re so hostile to the idea that we would be influenced by foreigners,” said the lawyer, Meredith Fuchs. “In a sense they are really elevating the concerns of non-U.S. entities.”

“On the one hand, it is contrary to a very Republican ideological view. On the other hand, it’s not inconsistent with their secretive philosophy,” she said.

A research analyst at the Federation of American Scientists, Steven Aftergood, said the deference to the U.N. was being used as a “pretext.”

“The Bush administration puts a premium on nondisclosure,” Mr. Aftergood said, adding: “If there’s a way they can withhold information, they will do so.”

In December, a federal judge in California ruled that the Defense Department had authority to defer to the International Committee of the Red Cross in rejecting a reporter’s request for documents about the humanitarian group’s visits to the American base at Guantanamo Bay.

The judge said an exception in federal law allowed the records to be kept secret, even though the Red Cross made repeated public statements critical of the American military installation there, which houses prisoners from the war on terror.

Mr. Aftergood said the dispute over the oil-for-food documents is an indication of how the Freedom of Information Act is often impotent when diplomatic concerns are at stake.

“It’s a recurring problem, particularly in the field of foreign policy,” Mr. Aftergood said. “If you visit the National Archives, you increasingly find withdrawal slips instead of historical records. Records that were public as recently as a few years ago have been removed.”

While the Bush administration has been vigorous in fighting freedom-of information lawsuits, previous administrations have also asserted the need to shield diplomatic communications from public view.

Under President Clinton, the Justice Department went to the Supreme Court to preserve the State Department’s right to keep secret a letter it received from United Kingdom officials regarding a criminal trial in Oregon of two cult members who were British nationals.

The Supreme Court case was dismissed after the British government abruptly released the document.

The Judicial Watch lawsuit, which was filed in federal court in Washington on Tuesday, has been assigned to Judge Ricardo Urbina.