Direct proof of use
U.S. Marine Corps History Division documents LAV-AT use during the Battle of al-Khafji in the 1990 Gulf War. Its battle history identifies seven LAV-AT light armored anti-tank vehicles from 1st Light Armored Infantry Battalion's Headquarters Company attached to Company D, 3d Light Armored Infantry Battalion, under Task Force Shepherd.
The same account places the attached LAV-AT section northwest of Observation Post 4 on 29 January 1991 and describes LAV-ATs moving forward with LAV-25s to cover a reconnaissance platoon's withdrawal. During the advance, one LAV-AT fired an anti-tank missile at what its crew believed was an Iraqi tank; the missile instead struck the friendly LAV-AT known as Green Two.
Sources: U.S. Marines in Battle Al-Khafji
Timeline
Company D was ordered to Observation Post 4 at midday on 29 January 1991 and established its LAV-AT section northwest of the post by about 1500. Later that evening, Iraqi tanks and armored personnel carriers advanced toward the observation post, and Company D prepared to meet the attack.
As the OP 4 fight developed, Captain Roger Pollard led LAV-25s forward with part of the LAV-AT section. The Marine Corps history describes the LAV-ATs using bounding overwatch because the vehicles had to stop to fire their missiles. After the friendly-fire loss of Green Two, Company D continued to engage Iraqi armor with missile and 25 mm cannon fire while also helping mark targets for coalition aircraft.
Sources: U.S. Marines in Battle Al-Khafji
Operational role
The documented Gulf War operator was the U.S. Marine Corps on the coalition side of the conflict. In the al-Khafji account, the LAV-ATs were attached to a light armored company rather than operating as a separate tank force. Each vehicle carried an Emerson 901A1 TOW 2 launcher, thermal imaging equipment, and a four-person crew, and the history identifies the LAV-AT section as Company D's primary anti-tank asset.
The clearest incident-level evidence is the Observation Post 4 fight, not a broad campaign inventory claim. The LAV-ATs were used for anti-armor fire support and overwatch during a night engagement against Iraqi armored forces crossing into Saudi Arabia. The record also shows the limits of the available evidence: the specifically described missile shot was a friendly-fire incident, while the later missile-fire reference is at company level and does not itemize each LAV-AT shot or target effect.
Sources: U.S. Marines in Battle Al-Khafji