You read this HorseHillary on World Net Daily,and there were several threads about it right here on FR. The "source" WND used was a wannabe liar named Thomas Sanchez who WND claimed was a Colonel in the Texas NG,and a professional intelligence officer with covert experience in VN. He also claimed to have seen a secret Executive Order that was "Eyes Only for the President" that stated this exercise was to train troops how to confiscate the weapons of US citizens. The reality was he was a self-promoted Colonel in the Texas Militia,and his "covert VN experience" was as a enlisted sailor floating off the coast of VN.
Sanchez was also the source WND was using as "proof" of UN troops rallying along the Mexican border.