Armed vigilantes are illegally detaining hundreds of migrants attempting to cross the southern US border, human rights activists have claimed.
Ex-military veterans dressed in camouflage and armed with semi-automatic rifles can be seen rounding up Central Americans on videos shared online.
The American Civil Liberties Union (ACLU) claimed the Trump administration’s “vile racism has emboldened white nationalists and fascists” to act outside the law.
In one video, thought to have been shot on Tuesday evening, UCP members are seen detaining hundreds of migrants. Many appeared to be families with children, who were then held until border patrol agents arrived.
“This group was so huge we wont [sic] have an accurate count until the [Border Patrol] is finished processing them,” the group wrote. “This needs to stop!!!!! Build the wall.”
Dozens more videos show similar detentions of the migrants – an increasing number of whom are seeking asylum in the US after fleeing gang violence in their home countries.
The organisation says its members “stand up for the rights of every American” and “help keep America safe”.
However, the vigilante detentions on the border have been condemned by the ACLU, which described UCP as a “fascist militia organisation”.
In a letter to New Mexico governor Michelle Lujan Grisham and state attorney general Hector Balderas, the ACLU alleged the detentions were illegal and called for an investigation into the situation.
It blamed Donald Trump anti-migrant rhetoric for encouraging the vigilante groups.
“[The United Constitutional Patriots’] actions undermine the legitimate efforts of our state’s law enforcement officials to keep New Mexico families safe and they erode community trust,” the letter added.
“The Trump administration’s vile racism has emboldened white nationalists and fascists to flagrantly violate the law.
“This has no place in our state: we cannot allow racist and armed vigilantes to kidnap and detain people seeking asylum. We urge you to immediately investigate this atrocious and unlawful conduct.”
The offices of Ms Lujan Grisham and Mr Balderas did not respond to requests for comment.
In March, then-US Customs and Border Protection commissioner Kevin McAleenan said authorities did not need the help of citizens to police the border.
“We are not asking for civil society groups to provide border security assistance,” he said during a visit to Texan city El Paso.
Additional reporting by Reuters