Heavily-armed members of a controversial right-wing "patriot" group added an extra dose of unease to protests in Ferguson, Missouri, early Tuesday.
The Oath Keepers organization says its members — all former military, police and first responders — pledge to "defend the Constitution against all enemies, foreign and domestic."
However, St. Louis County Police Chief Jon Belmar described their presence as "both unnecessary and inflammatory."
Protesters and police confirmed that a handful of Oath Keepers with what appeared to be assault rifles, bulletproof vest and camouflage gear were seen early Tuesday on the streets of Ferguson, which was under a state of emergency following demonstrations pegged to the anniversary of Michael Brown's death.
Several protesters confronted members of the group, asking why they were allowed to openly carry weapons.
"I'm happy that we're able to defend ourselves," one Oath Keeper replied in footage from NBC station KSDK. "It's been our right for a long time."
The St. Louis County Police Department said it would consult with the St. Louis County Prosecuting Attorneys Office about the legalities of the issue.
Missouri allows individuals with concealed weapons permits to openly display firearms, unless it is done in an "angry or threatening manner."
Shawn McGuire, a spokesman for St. Louis County Police, said he did not believe officers had confronted the Oath Keepers or told to leave.
"We do not know who sent them," he added.
The Oath Keepers organization did not immediately respond to a request for comment from NBC News. Members of the organization also were in Ferguson late last year when protests reignited over a grand jury decision not to indict the officer, Darren Wilson, who killed Brown.
The Southern Poverty Law Center describes the Oath Keepers as a "fiercely anti-government, militaristic group."
The organization — which claims to have more than 30,000 members — was founded in 2004 by former U.S. Army paratrooper and Yale Law School graduate Stewart Rhodes.
Rhodes has referred to Hillary Clinton as "Hitlery" and earlier this year said that Sen. John McCain should be tried for treason and "hung by the neck until dead" for going "along with the program of the destruction of this country."
Following the deadly attack on a Naval reserve center in Chattanooga, Rhodes issued a blistering critique of the Pentagon for failing to allow armed servicemen at recruitment centers and told Oath Keepers to take up station where they could.
"Go armed, at all times, as free men and women, and be ready to do sudden battle, anywhere, anytime, and with utter recklessness," he wrote on the organization's website. "That IS the price of freedom."
Patricia Bynes, Democratic Committeewoman of Ferguson Township, went to check on the protests early Tuesday and was surprised to find the Oath Keepers amid a heavy police presence.
"They just showed up, walking around carrying their assault rifles," she told NBC News. "There really was no need."
Bynes said the Oath Keepers' presence detracted from the real issues at heart: racial inequality.
"I would rather the story be on things we're working on in Ferguson and not the Oath Keepers," she said.
Several protesters asked the Oath Keepers to leave and questioned why the men were allowed to openly carry weapons given how protests over the past year have been to highlight racial inequality.
"If there were black and brown people in this country who showed up in the streets open carrying assault rifles in paramilitary garb would they still be received the same way?" Bynes asked. "It seems to be that especially when it comes to the Second Amendment there seems to be a different way that it is enforced."
The commiteewoman said that police did not confront the Oath Keepers — which hit to the core of the issues.
"There were two blocks of police. They saw them," she said. "It's more about the hypocrisy. Of wow, if anybody out here tried that they'd be met with a different greeting from police."
One Oath Keeper who identified himself as "John" acknowledged that if the average protester was armed in a similar way "it might invite some problems" but told NBC News that he and the others were "just Americans trying to keep our fellow men safe."
John said the group was working to protect the staff of Infowars, but the conservative website issued a statement denying it had hired any Oath Keepers to protect its journalists.
The Oath Keepers' website outlines a list of 10 "Orders" members will not obey — including orders to disarm the American people, conduct warrantless searches or "blockade American cities, thus turning them into giant concentration camps."
Included on the list are two which might have particular resonance in Ferguson. The fourth? "We will NOT obey order to impose martial law or a 'state of emergency' on a state."
And the final item: "We will NOT obey any orders which infringe on the right of the people to free speech, to peaceably assemble, and to petition their government for a redress of grievances."