The weapons may still be in the hands of Iraqi special units and could still be used against coalition forces there, the top U.S. military officer said Sunday.
Members of the 75th Exploitation Task Force found sites identified by Washington to be inaccurate, destroyed by looters, or both, the Post reports. The group is expected to leave next month.
The Bush administration cited the suspected presence of hundreds of tons of biological and chemical agents and evidence of an ongoing nuclear weapons program as the prime reason for launching the war against Iraq.
Air Force Gen. Richard Myers, chairman of the Joint Chiefs of Staff, said U.S. authorities "are asking ourselves" whether banned weapons may still be in the hands of Iraqi Special Republican Guard units that eluded capture when Saddam Hussein's regime collapsed last month.
"We try to interrogate (prisoners) with that (question) in mind," Myers told reporters during a visit to Qatar. "Were they full-deployed and could they have been brought to bear on us or are they still perhaps out there somewhere in some sort of bunker and could have been used? We are trying to run that one to the ground."
Many of Saddam's elite units failed to mount a credible resistance, leading to suspicions that some of them may be trying to reorganize
In other developments:
From November to March, U.N. weapons teams conducted more than 700 surprise inspections at hundreds of Iraqi sites, and did not report finding any weapons-making programs. A U.S. military unit of experts in unconventional arms that followed invading U.S. troops into Iraq in March, has surveyed 75 of 90 high-priority sites, and thus far also has not reported conclusive evidence of such programs.
The difficulty in finding any banned weapons now threatens U.S. and British plans to end U.N. sanctions against Iraq. Russian diplomats have said they need to see conclusive evidence that such programs have been eliminated before approving the lifting of the 13-year sanctions regime, and President Vladimir Putin has even raised the possibility that Saddam Hussein could still be alive and in possession of the deadly weapons.
High-ranking Iraqis in U.S. custody have uniformly denied that their government, ousted last month by the invasion force, had any weapons of mass destruction, U.S. officials say.
The deposed government maintained it destroyed its chemical and biological weapons by the early 1990s. It never succeeded in building a nuclear weapon.
Meanwhile, in the second such find this month, U.S. troops found a trailer they suspect could be a mobile biological weapons laboratory near the northern city of Mosul, a New York Times correspondent with the troops reported.
The trailer, stripped by looters, was located just outside the entrance of al-Kindi, Iraq's largest missile research and testing complex, according to the report posted Saturday on the Times' Web site. The trailer contained an air compressor, refrigerator, fermenter and dryer, items associated with a biological weapons lab, Maj. Paul Handelman of the 101st Airborne Division's chemical weapons team told the paper.
U.S. troops found a similar trailer in northern Iraq earlier this month, but the military has said it still has not confirmed whether it was used for biological weapons.