The American Civil Liberties Union of New Mexico on Thursday called for state authorities to investigate a group of armed US citizens they alleged are illegally detaining migrants entering the United States. The United Constitutional Patriots, who claim to be mainly military veterans, have patrolled the US-Mexico border near Sunland Park, New Mexico, since late February in search of illegal border crossers. They post videos showing members dressed in camouflage and armed with semi-automatic rifles holding groups of migrants, many Central American families seeking asylum, until US Border Patrol agents arrive. The small volunteer group says it is helping Border Patrol deal with a surge in undocumented migrants but civil rights organizations like the ACLU say it is a “fascist militia organization” operating outside the law. “We cannot allow racist and armed vigilantes to kidnap and detain people seeking asylum,” the ACLU said in a letter to New Mexico Governor Michelle Lujan Grisham and Attorney General Hector Balderas. “We urge you to immediately investigate this atrocious and unlawful conduct.” The offices of Lujan Grisham and Balderas did not respond to requests for comment. On a March 27 visit to El Paso, Texas, next to Sunland Park, then US Customs and Border Protection (CBP) Commissioner Kevin McAleenan said his agency, which runs US Border Patrol, did not need the help of citizens to police the border. “We are not asking for civil society groups to provide border security assistance,” said McAleenan, who was recently appointed acting secretary of the US Department of Homeland Security. US CBP did not respond to a request for further comment. UCP member John Horton did not immediately return calls. Horton has previously told media that UCP members are armed for self defense, as is their right under US law, and aware they cannot detain people entering the United States illegally. US armed groups have long patrolled the US border, their numbers rising during upticks in migrant apprehensions, such as during the mid 2000s when the Minuteman Project was established.