WASHINGTON (AP) - U.S. intelligence agents operating under the guise of U.N. arms control inspectors spied on the Iraq military for three years, The Washington Post reported yesterday.

Citing unidentified government employees and documents, the newspaper said the U.N. Special Commission was not aware it had been infiltrated by U.S. spies and did not authorize or benefit from the operation.

White House spokesman David Leavy acknowledged yesterday that intelligence was gathered by the United States, but he refused to comment directly on the allegation UNSCOM was kept in the dark.

''Everything that the United States did was to support UNSCOM in its effort to break Iraq's concealment of its weapons of mass destruction,'' Leavy said.

Clinton administration officials all along have acknowledged gaining valuable information about Iraq as a byproduct of its cooperation with UNSCOM in rooting out Saddam Hussein's forbidden missile, nuclear, chemical and biological weapons programs.

Leavy disputed claims U.S. intelligence directly used UNSCOM to penetrate Iraq's security forces and undermine the Iraqi regime.

''No intelligence that was gathered to support UNSCOM was used for Iraqi regime-change activities,'' he said. ''I would just note that not everything that is said by former employees should be taken as sacrosanct on this issue.''

The Post report comes in the wake of a Feb. 23 story in The New York Times citing galley proofs of a forthcoming book by former arms inspector Scott Ritter as saying he knew of Central Intelligence Agency operatives being placed on U.N. inspection teams.

Ritter, a former Marine officer, resigned last year as a U.N. inspector and accused the Clinton administration of undermining the inspectors' job.

Ritter has repeatedly complained that the administration's policy is ineffectual and wrong-headed, and in turn has been criticized by administration officials who have attempted to discredit his assertions.

Reversing an earlier stance, a Defense Department agency recently told Ritter he might need to submit his book for pre-publication security review in what Ritter's lawyer called an attempt at intimidation.

The Times reported that Ritter claims in the book, scheduled for publication in April, that he and a high-ranking CIA official organized some of the most intricate U.N. inspections and that CIA paramilitary covert operators were placed on the inspection teams.

An inspection team with nine CIA officials was in Iraq during a June 1996 coup attempt against Hussein and might have scheduled it, said Ritter, who according to the Times does not provide proof of all of his claims.

The Post report said U.S. agents rigged UNSCOM equipment and office space to intercept Iraqi military communications between commanders and infantry and armored forces in the field.

American intelligence agents infiltrated the system when UNSCOM changed the arrangement it used to monitor distant sites in Iraq with video cameras. The U.S. technicians who installed and maintained the system were intelligence operatives, and they hid antennas capable of intercepting transmissions in the equipment, the newspaper said.

At least two other technicians lent by the U.S. government to run the remote camera system for UNSCOM were employees of the CIA, according to the Post.