Pentagon sending 5,200 troops to help block migrant 'caravan'

The Pentagon will deploy 5,200 active-duty troops to assist the Department of Homeland Security in "hardening" the U.S.-Mexico border by the end of the week to help stop a migrant "caravan" of about 3,500 people, according to senior government officials.

Air Force Gen. Terrence O'Shaughnessy, head of North American Aerospace Defense Command and U.S. Northern Command, told reporters at a press conference today that some of the troops will be armed, but will be operating in line with federal laws barring military personnel from directly conducting law enforcement activities.

"The units that are normally assigned weapons, they are in fact deploying with weapons," he said.

The Pentagon has not yet announced the cost of the operation. For comparison, Operation Jump Start, which lasted from May 2006 to July 2008 under former President George W. Bush, cost $1.2 billion and involved approximately 6,000 Guard troops, according to the Government Accountability Office.

O'Shaughnessy said the troops will provide logistical, operational, engineering and medical support to U.S. Customs and Border Patrol forces, such as rapid transportation via C-130 and C-17 aircraft and using military-grade sensor equipment to spot unidentified groups of people crossing the border.

O'Shaughnessy's forces, which will be deployed in addition to the 2,092 National Guard personnel already at the border, will be laying 22 miles of concertina wire and setting up other fencing and temporary vehicle barriers.

CBP Commissioner Kevin McAleenan said the caravan of migrants seeking asylum is currently moving across southern Mexico, while a second large group is massing at the Mexico-Guatemala border.

"The caravan has already been offered protections in Mexico," he said, adding that the group should seek asylum there.

The caravan has become a political live-wire before congressional mid-term elections, with Democrats claiming President Trump has sought to stoke fear around the issue to energize the GOP voting base.

Trump, meanwhile, has made unsubstantiated claims about the dangers posed by the caravan, which he has labeled an "invasion," though it remains weeks away from the U.S. border.