Anywhere from seven to 15 vehicles are being tested for possibly containing biological or chemical weapons and for serving as mobile weapons labs, Fox News has learned.

Fox News' Rick Leventhal — embedded with the 2nd Battalion, 23rd Marines in Baghdad — reported Friday that an Army intelligence unit was heading toward a suspect vehicle Friday where they will test for the presence of chemical or biological agents.

Capt. Aaron Robertson, an intelligence officer, told Fox News that there are seven to 15 vehicles in proximity to that suspect vehicle that they will be searching. Other vehicles have raised similar concerns, but they do not yet know if they are rigged with the same devices that may imply they were used for manufacturing such harmful agents.

Robertson said gas masks and chemical suits were also discovered near the suspect site.

On Thursday, Army investigators looked inside what appeared to be a refrigerator truck at a construction site and saw what looked like a surface-to-air radar vehicle. But hidden inside fake side panels were an electronic pulley system, open jars and containers, a winch and hooks meant to move apparatus for rinsing and cooling substances without manual help.

Investigators from Echo Company said the system resembled a hazardous-materials lab, where substances could be mixed, cooled and heated without direct human contact.

Anti-aircraft guns, a surface-to-air missile and several caches of weapons and ammunition were also found at the site.

It was suspected that the truck may have been a mobile biological weapons lab. However, on Friday the Army said that specific vehicle was deemed not to be such a lab, but that the seven to 15 others discovered on the site are still being investigated.

Defense Secretary Donald Rumsfeld has stressed that any substances or weapons found to be containing banned agents will be tested not only by U.S. weapons experts, but by others across the globe to be sure of the results.

The Bush administration has long argued that Saddam's regime has possessed banned weapons, yet U.N. weapons inspectors didn't exactly find any smoking guns when they returned to Iraq this year to check out various sites.

The White House has conceded that the mobile weapons labs may be hard to find because of their mobility.

White House officials on Thursday expressed "high confidence" that weapons of mass destruction will be found in Iraq. And they said that with the fall of Saddam, Iraqis will likely be more willing to lead American experts to the banned arms.

Over three weeks of war, coalition forces have checked out dozens of suspect sites — hunting for chemical, biological and nuclear arms materials. So far, no finds have been confirmed.

U.S. officials told Fox News that CIA officers are in Baghdad and throughout Iraq looking for scientists to point out the locations of Iraq's weapons of mass destruction.

Special operations teams are also trying to find and test possible weapons materials at 1,000 sites. Senior defense officials said, "The list has grown ... and [the teams] have only been through a small number of sites (fewer than 20)."

But White House Press Secretary Ari Fleischer noted Thursday that the Iraqi regime has proven itself a master of hiding banned weapons.

Fox News' Rick Leventhal and Liza Porteus and The Associated Press contributed to this report.