SUNLAND PARK, N.M./TAOS, N.M. (Reuters) - A group of armed Americans who have been stopping migrants illegally crossing the U.S.-Mexico border abandoned their New Mexico camp on Tuesday, days after its leader was arrested and allies deserted them during a storm of criticism.

The old (bottom R) and the new border fence dividing U.S. and Mexico is seen from Tecate, Mexico April 4, 2019. REUTERS/Carlos Jasso

Still clad in their camouflage uniforms, the remaining handful of gunmen drove out of the Sunland Park, New Mexico, encampment after two months spent detaining thousands of illegal migrants.

The abrupt departure of the paramilitary group, the United Constitutional Patriots (UCP), followed allegations they had kidnapped migrants and an ultimatum by the Union Pacific Railroad for them to leave the area in 30 minutes after the company accused the group of trespassing.

Larry Hopkins, leader of the UCP, appeared in court in Las Cruces, New Mexico, on Monday to face firearms charges following his arrest by the FBI at the weekend.

“They were saying they’re just tired of this B.S. and they’re going back to their homes,” Sunland Park Police Chief Javier Guerra said. “As of today, they won’t be out there harassing anybody.”

UCP members did not respond to requests for comment.

Carrying semi-automatic rifles and wearing black ski masks, UCP members claimed to have detained some 5,600 migrants in the past 60 days, most of them Central American families seeking asylum, before handing them over to U.S. Border Patrol.

UCP spokesman Jim Benvie said on Saturday local Border Patrol gave the group operating guidelines, such as not to touch migrants, and to shoot only if they were shot at.

“We wouldn’t be there if they didn’t want us there,” Benvie said. “They just can’t publicly say that.”

El Paso Sector Border Patrol spokesman Ramiro Cordero declined to comment beyond a statement released by U.S. Customs and Border Protection that the agency did not support U.S. citizens taking law enforcement into their own hands.

Cordero said in a March interview with Diario de El Paso the UCP had helped Border Patrol by telling them what was going on in the area, but stressed they could not carry out any law enforcement role.

‘PIN THEM IN A BUSH’

The UCP’S numerous online videos show members stopping migrant groups, sometimes in the hundreds, herding them and telling them to sit and wait for Border Patrol agents to arrive.

The American Civil Liberties Union accused the group on Thursday of being a “fascist militia” with no authority to detain or arrest migrants. Other critics accused members of impersonating law enforcement with their military-style uniforms with eagle insignias.

“We try, with a verbal command, to stop them running, because we’ve seen women with babies in backpacks jump down that rock hill next to the railroad tracks,” Benvie said. But he said the group tried to trap migrants who did run, suspecting them of being criminals.

“If we can do something to slow them down and locate and pin them, we’ll pin them in a bush,” he said. “Then we call Border Batrol and say, ‘Hey, we’ve got a guy in a bush’.”

New Mexico Attorney General Hector Balderas said in a statement to Reuters on Tuesday he is working with local leaders to ensure the safety of the community.

“The rule of law is vital to securing our borders,” he said.

New Mexico Governor Michelle Lujan Grisham, a Democrat, said on Friday the UCP’s activities had to stop and ordered an investigation of the group.

The Federal Bureau of Investigation moved in on Saturday to arrest Hopkins on 18-month-old weapons charges.

Hopkins, also known as Johnny Horton, appears in Youtube videos as a country singer and previously served two prison terms for violating gun laws.

He has a history of falsely claiming to be a government agent, court and police documents show.

The FBI affidavit against him stated that a witness said in 2017 his group was training to assassinate financier George Soros, former Secretary of State Hillary Clinton and former President Barack Obama.

Former supporters began to desert the UCP after the charges.

In March, Gavin Clarkson, a Republican candidate for a New Mexico U.S. Senate seat, appeared in a 30-minute video with UCP members praising their work on the border.

On Saturday he lashed out at them. “Masked militiamen are the antithesis of what a free republic looks like. I absolutely condemn their lawless activities,” Clarkson said on Twitter.