As the military advances closer to Baghdad, signs of Iraqi chemical preparedness are multiplying, although there is still no conclusive evidence Saddam Hussein's regime possesses weapons of mass destruction.
On Friday, troops at a training facility in the western Iraqi desert came across a bottle labeled "tabun" -- a nerve gas and chemical weapon Iraq is banned from possessing.
Closer to Baghdad, troops at Iraq's largest military industrial complex found nerve agent antidotes, documents describing chemical warfare and a white powder that appeared to be used for explosives.
U.N. weapons inspectors went repeatedly to the vast al Qa Qaa complex -- most recently on March 8 -- but found nothing during spot visits to some of the 1,100 buildings at the site 25 miles south of Baghdad.
Col. John Peabody, engineer brigade commander of the 3rd Infantry Division, said troops found thousands of 2-by-5-inch boxes, each containing three vials of white powder, together with documents written in Arabic that dealt with how to engage in chemical warfare.
Initial reports suggest the powder is an explosive, but tests are still being done, a senior U.S. official said. If confirmed, it would be consistent with what the Iraqis say is the plant's purpose, producing explosives and propellants.
According to U.N. weapons inspectors, who spoke on condition of anonymity, the Iraqis filled warheads and artillery shells with explosives at the site and manufactured bomb casings there. The activities, for conventional weaponry, were allowed under U.N. resolutions. But the resolutions, passed after the 1991 Gulf War, ban Iraq from possessing chemical, biological and nuclear weapons and the long-range missiles to deliver them.
Peabody told an Associated Press reporter that troops at al Qa Qaa also discovered atropine, used to counter the effects of nerve agents, and 2-PAM chloride, which is used in combination with atropine in case of chemical attack.
The presence of atropine, and the discovery of gas masks and chemical suits earlier in the war, could indicate Iraq was preparing to use chemical weapons.
For years, the al Qa Qaa site has raised the suspicions of weapons inspectors who believed the facilities could be converted for the production of missiles and chemical and nuclear weapons. It was visited repeatedly during the 1990s and during the last cycle of inspections -- between Nov. 27 and March 17 -- when U.N. experts went to the complex more than 10 times.
According to a British dossier on Iraq published last September, parts of al Qa Qaa's chemical complex, destroyed in 1991, were repaired and are now operational, including a production plant for the chemical weapon phosgene.
Nuclear inspectors believe an area of the complex was involved in designing an atomic bomb before Iraq's nuclear program was destroyed by U.N. teams after the 1991 Gulf War. The facility also made lenses and other components that can be used to trigger nuclear explosions.
In March 1990, customs officers at Heathrow Airport in London seized a case of capacitors -- components for triggers in nuclear weapons -- bound for al Qa Qaa that were especially designed for detonating nuclear warheads.
Inspectors had installed cameras and sensors around the complex after the Gulf War but the Iraqis dismantled the equipment when inspectors left in 1998. The U.N. inspectors who returned in November had planned to install new monitoring equipment but ran out of time.
Much is riding on the disarmament process.
The United States believes Iraq has chemical and biological weapons and a reviving nuclear weapons program.
But the Bush administration was unable to convince much of the world in the run-up to the war.
Countries including France and Russia blocked the United States from winning U.N. support for the war partly because they saw no proof that Iraq possessed such weapons. The chief weapons inspectors reported several times that they had found nothing to support the administration's claims.
So far, invading U.S. forces have not found chemical or biological weapons. Officials and former weapons inspectors have said discoveries were likely to be made closer to Baghdad. Several large facilities, such as al Qa Qaa, are within 50 miles of the capital.
"We believe that this regime does possess weapons of mass destruction, we remain convinced of that," U.S. Brig. Gen. Vincent Brooks said Friday. He said some weapons may have been pulled into the Baghdad area, "either delivery systems, or, potentially, storage systems."
But a discovery far from the Iraqi capital was made Friday when troops in the western desert came across what they believe is a training center for nuclear, chemical and biological warfare, Brooks said.
One bottle found at the site was labeled "tabun" -- a nerve agent that the U.S. government says may have been used during the 1980-88 Iran-Iraq war. There was no way to immediately confirm whether the substance was indeed tabun and soldiers found only a small amount, indicating the site was meant for training, not storing or deploying chemical weapons, Brooks said.
"In that particular site, we believe that was the only sample," he said. "That's why we believe it was a training site. Our conclusion is that this was not a (weapons of mass destruction) site ... it proved to be far less than that."
Photos of the site showed shelves of brown bottles with yellow labels. Brooks said troops did not understand some of the labels and were collecting the bottles for examination.
Iraq declared to U.N. inspectors the overall production of 3,859 tons of chemical weapons agents. According to Iraq's declarations, mustard, tabun and sarin were produced in large quantities. Iraq also admitted production of 3.9 tons of the deadly nerve agent VX.
Subsequently, inspectors destroyed 116 tons of tabun and more than 1,000 tons of ingredients for brewing up the nerve gas.
Iraq has repeatedly claimed that it destroyed its unconventional weapons programs after 1991. The claim was voiced again on April 1 by Iraqi Vice President Taha Yassin Ramadan. Referring to the gas masks and other chemical gear found by advancing coalition troops, he suggested U.S. forces were planning to plant evidence to implicate Iraq.
"Let me say one more time that Iraq is free of weapons of mass destruction," he said. "The aggressors may themselves intend to bring those materials to plant them here and say those are weapons of mass destruction."