I'm not entirely sure of this report, but:

The incursion into U.S. territory last week by "Mexican gunmen" was not a chance confrontation between the Arizona National Guard and untrained illegal immigrants, but a deliberate "perimeter probe" by an infantry-trained, uniformed Mexican force, officials say.

Euphoric Reality has learned in exclusive interviews with high-ranking sources within both the Arizona National Guard and the U.S. Border Patrol that the incident the mainstream media calls a "standoff" was in reality a military-style operation, carried out by a unit of Mexican troops dressed in military uniforms, flak jackets, and armed with AK-47s in an apparent operation to probe the border defenses and test the limits of the National Guard troops. Using easily recognizable infantry movement tactics (such as arm and hand signals and flanking maneuvers), the Mexican unit deliberately moved in a military formation across the border from Mexico, where they were picked up by National Guard surveillance...

One of the statements that leaves me less sure of it is the claim that the Mexican force was inside the U.S. - or at least being observed by the National Guard - for three hours before the incident. I don't know exactly how far inside the U.S. it occured, but that seems to conflict with the claim that they could retreat quickly back over the border.