U.S. troops on Friday found thousands of boxes of white powder, nerve agent antidote, unidentified liquid and Arabic documents on how to engage in chemical warfare, U.S. military officials said.

Forces made the discovery at an industrial site south of Baghdad.

Reuters reported that they also found a second site containing vials of unidentified liquid and white powder. A U.S. officer said the site was close to the other plant, at the Latifiyah industrial complex, about 25 miles south of Baghdad, where soldiers had found the other vials and manuals.

"It is clearly a suspicious site," Col. John Peabody, engineer brigade commander of the 3rd Infantry Division, said of the first site.

Also discovered was atropine, used to counter the effects of exposure to chemical agents, and 2-Pam chloride, which is used in combination with atropine in case of chemical attack.

But a senior U.S. official in Washington who is familiar with initial testing said the materials at the first site were believed to be explosives.

"Initial reports are that the material is probably just explosives, but we're still going through the place," the official said.

The plant itself was shown on U.S. military maps as including underground storage facilities, Reuters reported. Some contained liquid, some powder. The books and manuals were in a safe, Captain Kevin Jackson told Reuters near Baghdad.

Peabody said troops found thousands of 2-inch 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.

The facility had been identified by the International Atomic Energy Agency as a suspected chemical, biological and nuclear weapons site. U.N. inspectors visited the plant at least a dozen times, including as recently as Feb. 18.

The facility is part of a larger complex known as the Latifiyah Explosives and Ammunition Plant al Qa Qaa.

Brig. Gen. Vincent Brooks told reporters during a U.S. Central Command briefing in Qatar Friday that special forces in Iraq's western desert also found what they believed to be a training school for handling nuclear, chemical and biological warfare in the western desert of Iraq.

At least one bottle of the deadly chemical weapon, Tabun, was reportedly found. Tabun is a clear, colorless and tasteless liquid with a slightly fruity odor, and is lethal.

If skin absorption is great enough, death may occur in one to two minutes, or it may be delayed for one to two hours. Lethal respiratory dosages kill in one to 10 minutes, and liquid in the eye kills almost as rapidly.

The U.S. government says the nerve agent may have been used during the 1980-88 Iran-Iraq war. The soldiers found only a small amount of the chemical, 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," Brooks 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 by experts.

During the 1991 Gulf War, U.S. jets bombed the Latifiyah plant.

Iraqi Information Minister Mohammed Saeed al-Sahaf said Friday Iraq had no plans to use chemical or biological weapons against invading coalition despite a threat in the same breath to use "non-conventional" methods.

"But we will conduct a kind of martyrdom operations," he said during a press conference.

On April 1, Iraqi Vice President Taha Yassin Ramadan, in a statement on Iraqi television, repeated Baghdad's position that it had no weapons of mass destruction. Referring to reports that gas masks and other chemical gear had been found elsewhere in the country, he said the coalition might plant weapons of mass destruction 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."

Brooks said it's possible there are other weapons of mass destruction buried in the desert or stored in other locations.

"There are places we think weapons may have been stored," Brooks said in response to a reporter's question as to how coalition forces will avoid harmful contact with such weapons. "We don't want to create a weapons of mass destruction hazard … only the regime knows where they are for sure."

Earlier this week, Fox News reported that evidence was found in the Kurdish-controlled regions of northern Iraq that the Islamic militant group Ansar al-Islam was working on three types of chlorine gas and ricin and has ties to Al Qaeda.

U.S. sources said that documents and equipment were found in the rubble of an Ansar facility were described as "a cookbook and kitchen" for chemical weapons.

Fox News' Liza Porteus, Carl Cameron and The Associated Press contributed to this report.