To Fox News, civilians who show up toting assault weapons to voluntarily “guard” military recruiting centers -- as many have done since the recent attack in Chattanooga, Tennessee -- are “stepping up” in “a very patriotic move” and “protecting our military.” But the U.S. Army reportedly says armed civilians who stand outside of these facilities may “mean well” but the military “cannot assume this in every case” and such situations should be reported to local law enforcement.

On the morning of July 16, a 24-year-old man drove to a military recruiting center in a Chattanooga strip mall and opened fire, spraying the storefront's bulletproof glass with dozens of rounds fired from an assault weapon. He then drove to a nearby naval facility and killed four Marines and one sailor before being fatally shot by police.

In the wake of the shootings, civilians in several states that allow open carry of assault weapons donned camouflage or tactical gear and “stood guard” outside military recruitment centers in what they call “Operation Hero Guard.”

Fox News figures have applauded the phenomenon, but the U.S. Army Command Operations Center has circulated a letter, according to Stars And Stripes, saying that the “well-meaning” armed civilians may actually be detrimental to the security of the military facilities they think they're protecting.

Most national media outlets have covered the story of armed civilians at military recruitment centers but Fox News has gone further, endorsing the practice and twice inviting volunteer guards on Fox shows to be interviewed.

On the July 22 broadcast of Fox & Friends, co-host Brian Kilmeade said “armed Americans now stepping up to guard recruiting centers across the nation” before interviewing one volunteer, who told him, “I have people on our Facebook page all the time that are a little bit further away that can't come here, and I said, 'Just go out and start it in your community, just one person can make a difference.'”

Later in the same broadcast, during a live report from a recruiting office in New York's Times Square, Fox News legal analyst Peter Johnson, Jr. criticized current policies on who can carry guns at military facilities, and described “a citizen militia that is protecting our military across the country, showing up with AR-15s and weapons to say 'we stand with you.'”

The July 22 broadcast of Fox News' America's Newsroom saw host Martha MacCallum telling viewers, “In some towns, volunteers are already out there standing guard in a very patriotic move to protect those recruiting centers on their own because the military can't take any guns into those recruiting centers.” (Current regulations would actually allow authorized military law enforcement to carry firearms at military recruiting centers, although in practice law enforcement have not been assigned by the Department of Defense to these locations.)

During the July 21 edition of The Kelly File, host Megyn Kelly introduced her interview with one of the armed volunteers by saying that Obama “promised he can do what he can to keep our military safe, our next guest isn't betting on it.”

But according to a policy letter reportedly issued by the Army Command Operations Center-Security Division and obtained by Stars and Stripes, armed civilians are not necessarily improving the security of military recruitment centers. The letter says that the Army is “sure the citizens mean well, but we cannot assume this in every case and we do not want to advocate this behavior.”

According to Stars and Stripes, the letter instructs military recruiters not to approach armed civilians and adds, “If questioned by these alleged concerned citizens, be polite, professional and terminate the conversation immediately and report the incident to local law enforcement.” Recruiters are also instructed to file an Army security report following any interaction with armed civilians.

According to a spokesperson from Army Recruiting Command, instead of standing outside of recruiting centers with guns, “local communities can support our security by reporting suspicious activity, particularly around recruiting centers.”

The Stars and Stripes report noted that civilians affiliated with the Oath Keepers and “3 percenters” have been spotted with guns at recruiting centers. Both of these organizations are associated with the radical far-right fringe. The “3 percenter” movement was founded by militia leader Mike Vanderboegh as a force to violently overthrow a supposedly tyrannical federal government.

According to an analysis of public mass shootings over a 30-year period by Mother Jones, civilians with guns have never stopped attacks like the one seen in Chattanooga.