Responding to what they consider a call to arms, the Texas Minutemen, a militia group with members in several states, are sending at least 100 (some media say 200) volunteers to the Rio Grande who want to help stop the Central American migrant caravans.

It happened just as the first group of the 5,000 strong caravans, consisting of the largest group of migrants, arrived in Mexico City with more on the way.

Some 450 people, mostly men and boys, were given temporary shelter at a sports stadium as they waited for the others to arrive. Two other migrant caravans are also walking towards the US border.

Over in Texas, Mr Shannon McGauley, a bail bondsman in the Dallas suburbs who is the current president of the Texas Minutemen said he was preparing to head for the Rio Grande in coming days himself.

His group already has members at three points of the state’s border with Mexico and expects to add 25 to 100 more people in the coming days.

Packed with coolers and tents, oiling rifles and tuning up aerial drones, with plans to form caravans of their own and trail American troops to the border, the Texas Minutemen said they would simply assist the troops and Border Patrol guards already in place: “We’ll observe and report, and offer aid in any way we can. We’ve proved ourselves before, and we’ll prove ourselves again.”

Defending the country against what President Trump sometimes refers to as “an invasion,” the Minutemen are said to have 1at least 00 volunteers en route to the Rio Grande who want to help stop the migrants, with more likely on the way.

Mr McGauley claimed:“I can’t put a number on it. My phone’s been ringing nonstop for the last seven days. You got other militias, and husbands and wives, people coming from Oregon, Indiana. We’ve even got two from Canada.”

Mr Manuel Padilla Jr., the top Border Patrol official in the agency’s Rio Grande Valley sector, said he plans to meet with community members whose lands are adjacent to the rives in the coming week to address any concern they may have: “We don’t have any specific information about the militias.”

“We have seen them in the past, and when things start getting really busy, we have to make sure to let the community know they’re out there. But they’re doing that on their own.”

McGauley confirmed that the Minutemen would have night-vision goggles and aerial drones with thermal sensing equipment, capable of operating in darkness. Any suspicious activity will then be reported back to authorities and the militia would, of course, heed any instructions from Border Patrol agents or military personnel.

Asked whether his group planned to deploy with weapons, Mr McGauley just laughed. “This is Texas, man.”