Armed militias continue to patrol the United States-Mexico border seeking to repel any migration north, but critics warn that these self-styled ‘freedom defenders’ lingering on private land represent a powder keg that could have “disastrous” consequences.

Near Brownsville, Texas, a group of private citizens simply known as the Patriots were invited to watch 21 acres of border land owned by Rusty Monsees. The group, Reuters reported, has been on the land since early summer, when news reports announced that unprecedented numbers of unaccompanied minors from Central America had crossed the border.

In the first half of 2014, around 52,000 children, among many others, attempted the trek, fleeing poverty, violence, and systemic abuse present in their home nations. Many have ended up warehoused in US military installations and other facilities awaiting their fate amongst an inhospitable, nativist climate. President Barack Obama has vowed some type of immigration reform via executive action in the face of an inert Congress. Yet Obama has said he will not move on reform until after congressional midterm elections in November.

The numerousmilitias along the border join the US Customs and Border Protection as well as the Texas National Guard. The Patriots Information Hotline, a networking call center, claims 22 groups of “armed patriots” are patrolling the border, from Texas to California.

The US Border Patrol has warned that armed vigilantes taking intimidation tactics too far could have "disastrous personal and public safety consequences."

Yet the Patriots back in Brownsville insist the description “vigilante” is unfair, and that they are not itching to fire their high-powered firearms.

"Everybody has this bad taste in their mouth about 'militias.' They think we're out here trying to smoke people and kill them as soon as they cross the border. Which obviously, is not the case," said "Huggie Bear," a member of the Patriots who is a former US Army infantry team leader.

"Our goal here is to try to deter them from coming. They see us, they don't know who we are, so that kind of scares people away for a while,” he told Reuters.

Militia groups on the border have been invited by private landowners to patrol in certain areas, as is the case with the Patriots near Brownsville. Expenses are usually paid by the militia members, with sympathetic donors also offering support funding, according to Reuters.

Monsees said he asked for help on his border land given "illegals" have allegedly poisoned his dogs and shot at his house. "If they [the militia] leave, I'm dead," he said.

Others in the area echo these sentiments, saying the militia groups give them a sense of peace.

"Whoever says there's not a problem by the border wall, they don't live out here," said Fernando Rivera Jr., a property owner in Brownsville. Rivera said his son patrols the family’s backyard with a shotgun to deter what he calls criminals from crossing the border.

"Now, when they're on patrol, it's actually peaceful," Rivera said. "The dogs don't bark as much. I can actually get some sleep."

The militaristic Patriots are also equipped with all-terrain vehicles, thick body armor, plastic handcuffs to detain migrants and communications equipment that can supposedly reach Border Patrol agents.

The only live fire the group has encountered, according to Reuters, was from Border Patrol, who thought an armed member of the Patriots was an undocumented immigrant. Once shots were fired, the Patriot reportedly dropped his firearm. No one was injured in the encounter.

The situation exemplifies the challenges and worries the militias pose to law enforcement.

"When there are situations with any individual who is bearing arms in public or on private property, there is always a concern amongst law enforcement of possible misidentification that can lead to friendly-fire tragedies," said Eddie Guerra, sheriff of Hidalgo County in Texas.

Regardless, groups like the Patriots stay vigilant.

"If you spot them and shine your light on them, that lets them know that you're there," said Will, 25, who came from Indiana to join the Patriots. “Nine times out of 10, they're not going to come over.

"Even if they are going to try to cross again, we're still making it harder for them, and that's the reason we're here."