The Pentagon is preparing to send several thousand more active duty troops to support Customs and Border Patrol (CBP) personnel at the U.S. southern border, the department’s top civilian said Tuesday.

The ongoing troop deployments, which first began in October 2018, provided the Department of Homeland Security (DHS) with logistics and medical support, installation of concertina wire, and monitoring and surveillance aid, Acting Defense Secretary Patrick Shanahan told reporters at the Pentagon.

Photo of U.S. border with Mexico. U.S. is on the left. Parson has done border security work with Customs and Border Protection. Photo: CBP

“Most recently, DHS has asked us to support them in additional concertina wire and expanded surveillance capability,” he said.

Army Lt. Col. Jamie Davis, a DoD spokesman, confirmed Shanahan’s comments in an emailed statement. “As the Acting Secretary said, we are supporting our federal partners on the border and that mission has been extended until September,” he said. “We are currently sourcing the units involved and there will be an increase of a few thousand troops. We will provide more clarity on the numbers when we have it.”

Shanahan emphasized that the U.S. military’s role to date has been that of support, “not about undertaking a law enforcement position.”

As Shanahan spoke to the Pentagon press corps in his first media engagement since becoming acting defense secretary Jan. 1, the newly Democratic-led House Armed Services Committee (HASC) gathered across the river in its first full hearing of the year to discuss the Defense Department’s role on the U.S. southern border.

New HASC Chairman Adam Smith (D-Wash.) said while the deployment of troops from the National Guard to the U.S.-Mexican border was not uncommon, “it is the active duty troops that caught the attention of this committee.”

“While border security is always a challenge, there’s really not much evidence that right at the moment it is a crisis that would call for the – if not unprecedented, then highly unusual – step of sending active-duty troops to the border,” he added.

HASC Democrats in the hearing queried Undersecretary of Defense for Policy John Rood and Vice Adm. Michael Gilday, director of operations for the Joint Staff, on the number of active duty personnel and the role they are playing at the border.

About 2,350 active duty troops remain deployed at the border, down from about 5,900 that were originally sent to bases in California, Texas and Arizona in October, Rood said. They are currently scheduled through the end of the month, but “one portion” of that number may remain in place through the end of fiscal year 2019 “in response to new requests,” he added.

Their main mission has been to lay 70 miles of concertina wire on top of existing barriers, which has “hardened” 22 points of entry and allowed CBP to spread manpower more efficiently, and create barriers out of shipping containers, Rood said. DoD has also sent medical and facilities personnel to assist the Department of Health and Human Services, he noted.

The active troop deployment is expected to cost taxpayers $132 million by the end of the month, Gilday said. Meanwhile, the deployment of National Guard troops to the border is projected to cost $448 million in fiscal year 2019, up from $103 million in FY ’18, he added. A cost estimate for active-duty troops for FY ’19 is not available due to the “evolving and fluctuating” requirements,” Gilday noted.

The Defense Department chose to send nearly 6,000 troops at the start based on the request made by DHS, Rood added. At the time, the administration was concerned about a large caravan of asylum-seeking migrants making its way north through Central America and Mexico, and it was unclear where they would attempt to enter the United States.

By December, it became clear that the bulk of the migrants would attempt to enter the country via points of entry in California, and the Defense Department significantly reduced the number of troops in Arizona and Texas as a result, Gilday noted. However, the U.S. military is now tracking three additional caravans – one allegedly containing up to 12,000 individuals – heading north from Central America, leading to the request for additional troops, Rood said.

Having active duty troops in a supporting role has offered CBP agents more flexibility, the defense officials noted.

Committee members on both sides expressed concern about how an ongoing deployment would affect military readiness and questioned why National Guard troops were not sufficient to perform the requested duties. Gilday noted that the National Guard did not have sufficient personnel to perform the duty, and active duty troops were requested to fill the “delta.”

The department has taken pains to ensure the troops are rotated out “every six to eight weeks,” and while some personnel may have missed key training sessions in their units back home during their time at the border, the impact is expected to be minimal, he added.

“Most people think we’re just consuming readiness. … We’re also producing readiness,” he added. “You just accumulate that kind of hands-on leadership.”

Trump critics have accused the administration of playing politics by announcing the troop deployment just days before the 2018 midterm elections.

Rep. Elissa Slotkin (D-Mich.), a former CIA and DoD official first elected to Congress in 2018, said Tuesday that the timing of the deployment “makes it hard not to see this as political.”

Shanahan told reporters Tuesday he has had “lots of conversations with Chairman Smith” on the deployment of active duty personnel to the border.

Smith “wants to ensure that there’s transparency and oversight in his role,” he said. “He also has emphasized the importance of really being able to understand the policy behind the movement of people to the border, the role of the military in support of the Department of Homeland Security.”

Defense Daily reporter Matthew Beinart contributed to this report.