Armed vigilantes - many brandishing semi-automatic weapons - are stationing themselves outside gun-free military recruiting centers all over the country, claiming they are protecting troops following the recent killing of five servicemen in Chattanooga.

A group of five volunteers began standing guard outside the U.S. Armed Forces Recruiting Station in Clebune this week calling themselves 'Operation Hero Guard', with one carrying an AR-15,

Others set up camp outside stations in Alabama, Ohio, Virginia and Wisconsin in a similar protest.

The move came as the general tapped to be the next Army chief of staff said Tuesday that if legal issues could be resolved he thinks it would be appropriate to arm soldiers manning recruiting stations.

One of the members of the 'Hero Guard', Terry Jackson, an Army veteran with 15 years of service, said it felt it his duty to protect servicemen when they could not protect themselves.

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'Protect Our Troops': Jerry Blakeney, a member of Operation Hero Guard, stands guard outside a U.S. military recruiting station in Cleburne, Texas, on Tuesday, in honor of the Chattanooga shooting last Thursday

Vigilante: Gun-toting citizens such as Terry Jackson (pictured) are showing up at military recruiting centers around the country, saying they plan to protect recruiters following last week's killing of four Marines and a sailor in Chattanooga, Tennessee

Jerry Blakeney stands guard with other members of Operation Hero Guard outside a U.S. military recruiting station in Cleburne, Texas

On guard: Tyler Pinkston (left) and Jerry Blakeney (right) members of Operation Hero Guard, stand guard outside a U.S. military recruiting station in Cleburne, Texas, Tuesday

Terry Jackson, left, and Jonathan McCroskey, members of Operation Hero Guard, stand guard outside a U.S. military recruiting station in Cleburne

Protest: A man from Huntsville, Alabama, holds a gun while standing watch in front of the Armed Forces Career Center in Huntsville on Monday

Armed: Allen Bowles (left) and Clint Janney (right) stand guard outside a military recruiting center in Columbus, Ohio. The men are members of the '3 Percent Irregulars Militia', and say they plan to protect the center until the government provides its own security

David Walters (left), and Chip Beduhn stand guard outside an Armed Forces Recruiting Center in Madison, Wisconsin as part of a group of veterans guarding military recruiters

Jackson confirmed his protest was against the ban on weapons in such buildings after the Chattanooga shooting last Thursday, when a gunman killed four Marines and a sailor, and wounded another Marine.

Military recruitment centers are gun-free zones across America.

'It was unacceptable for our soldiers, sailors, our men and women of the military to go over and serve and go into combat, and then to come back here to the homeland and be gunned down on their home duty stations,' Jackson told The Fort Worth Star-Telegram.

'They were going to work for their families and not coming home.'

Since the shootings, Marines have been told to not wear uniforms at recruiting centers, which are often in strip malls.

However, two days after the shootings, the governors of Texas, Florida and Indiana ordered the arming of National Guardsmen at military offices and other facilities, along with the installation of bulletproof glass and more efficient video surveillance equipment.

The following day, Louisiana, Oklahoma, and Arkansas announced they too had brought in reinforcements.

Utah Governor Gary Herbert also announced they would 'explore additional ways to protect our men and women serving in the Armed Forces'.

Taking a stand: US Gen. Mark Milley, who is tapped to be the next Army chief of staff, said Tuesday he believes recruiting stations should be armed under 'certain conditions'

This unnamed man in Virginia recently joined a growing body of voices calling for an end to the gun ban on military recruitment offices after the Chattanooga shooting

Gen. Mark Milley responded to questions about the deaths of four Marines and a sailor in Chattanooga, Tennessee, at his nomination hearing before the Senate Armed Services Committee on Tuesday.

Authorities said Kuwait-born Muhammad Youssef Abdulazeez, 24, of Hixson, Tennessee, unleashed a barrage of fire at a recruiting center in Chattanooga, then drove several miles away to a Navy and Marine reserve center, where he shot and killed the Marines, and wounded the sailor, who later died.

Abdulazeez was shot to death by police.

'I think under certain conditions on both military installations and ... recruiting stations ... we should seriously consider it,' Milley said.

'In some cases, I think, it's appropriate.'

Tucked in strip malls in rural and suburban communities and in high-traffic city spots like New York's Times Square, military recruiting and reserve stations are designed to be open and welcoming to the public.

The troops inside aren't allowed to carry weapons.

The ban is largely due to legal issues, such as the Posse Comitatus Act of 1878, which prohibits the federal government from using the military for domestic law enforcement. U.S. forces don't routinely carry guns when they are not in combat or on military bases.

Investigation: Members of the FBI inspect the glass doors which are riddled with bullet holes at the military recruitment center in Chattanooga

Deadly attack: The silver convertible used by Muhammad Youssef Abdulazeez was pictured at the scene of the second attack where he was shot dead

Smirking: Muhammad Youssef Abdulazeez, 24, smiles in a mugshot following his arrest for driving under the influence in April. He was also an amateur MMA fighter

And Pentagon officials are sensitive to any appearance of armed troops within the United States.

The U.S. military has outlined security upgrades for recruiting stations, reserve centers and other facilities.

Military officials said security at recruiting and reserve centers will be reviewed, but Gen. Ray Odierno, the Army's current chief of staff, has said it's too early to say whether the facilities should have security guards or other increased protection.

He said there are concerns about accidental discharges and other security issues related to carrying loaded weapons.

Just outside Atlanta, a recruiter accidentally shot himself in the leg with his personal .45-caliber pistol while discussing the Tennessee shootings with one of his recruits.

Officials said he showed the sailor the unloaded gun, then reloaded it and inadvertently discharged it as he was putting it back in his holster.

Milley currently is head of U.S. Army Forces Command at Fort Bragg, North Carolina.

Prior to taking the Forces Command job in August 2014, Milley was the commander at Fort Hood, Texas.