No Conclusion Yet on Suspected 'Biolab'

American experts are withholding judgment on a trailer described by Washington officials as a suspected Iraqi mobile laboratory for biological weapons, the commander of the U.S. military's weapons hunting unit said Thursday.

"There's been no conclusion yet," said Col. Richard R. McPhee.

He said specialists were examining the vehicle, which Pentagon officials on Wednesday said was seized April 19 at a Kurdish checkpoint in northern Iraq.

As for when a determination might be made, "it'll be soon," said McPhee, commander of the 75th Exploitation Task Force, a unit of experts on chemical, biological and nuclear weapons charged with searching for such unconventional arms in Iraq.

Allegations that Baghdad was pursuing programs to build weapons of mass destruction were the key reason cited by the Bush administration in ordering the U.S. invasion of Iraq. In dozens of site inspections thus far, the U.S. experts have found no such weapons, nor did U.N. weapons inspectors find any at hundreds of sites visited before the war.

If the U.S. government concludes the confiscated trailer is a bioweapons lab, it would be the most concrete evidence uncovered of a hidden Iraqi program to produce prohibited weapons.

In Washington on Wednesday, the undersecretary of defense for intelligence told reporters the trailer was painted in a military color scheme and was found on a transporter usually used for tanks.

Stephen Cambone said the vehicle contained a device for fermentation and a system to capture exhaust gases -- equipment associated with Iraqi mobile bioweapons labs described to U.S. authorities by an Iraqi defector.

The Pentagon official said experts "have not found another plausible use for" the trailer, other than the kind of weapons work described by the defector.

Saddam Hussein's government, driven from power last month by the U.S.-British invasion, developed some biological weapons in the late 1980s. But it claimed to have destroyed all by the early 1990s, as U.N. inspectors enforced the ban on weapons of mass destruction ordered by the U.N. Security Council after the 1991 Gulf War.

During four months of resumed inspections beginning last November, U.N. teams inspected potentially suspicious vehicles to check the defector's story about mobile labs, but found none.

McPhee, in an interview, said one of his "CBIS" teams -- for Chemical-Biological Intelligence Survey -- had done an initial examination of the trailer seized in the north.

"It's still a suspected lab," he said. "Exploitations on that vehicle are still being conducted." "Exploitation" is U.S. military jargon for a thorough examination.

The commander, whose task force is based near Baghdad's international airport, said a new team would come to Baghdad to make a final determination on the trailer. But, he said, "the makeup of that team is to be determined."

He did not elaborate, except to say its members would provide "more expertise" and would not come from within his unit.

Cambone said on Wednesday the inspection was hampered by the fact that part of the trailer had been washed with a caustic substance, which would make testing for residues more difficult.