The Pentagon is sending 1,115 additional troops to the U.S.-Mexico border from over half a dozen units across the different services in support of the Trump administration?s immigration crackdown, the military announced Thursday.

They will join more than 8,000 troops on active-duty orders who have been added to the mission since late January, though a spokesperson for U.S. Northern Command emphasized to Military.com that not all of those supporting the mission are directly on the border, with some involved in air or maritime missions or even participating from their home station in some capacity.

The additional troops announced this week are considered ?ground components,? however, and are charged with providing additional logistics, engineering and medical capabilities as part of the military?s effort to ?gain full operational control of the southern border,? according to officials and a Northern Command news release.

The spokesperson, Air Force Capt. Mayrem Morales, said that the additional deployment of more than 1,000 troops was not the result of ?any specific event,? but rather part of the buildup of troops supporting the mission. When asked when those service members will deploy, Morales said that is still ?to be determined.?

?Ground units supporting the southern border mission are located across the southern border from Texas to California,? she said in an emailed statement. ?However, please know that not all announced units may be at the southern border at this time.?

In January, Trump administration officials initially considered sending 10,000 troops to support the border mission. As the buildup grows, the administration has increasingly relied upon military assets to fulfill not only its border security aims, but also its deportation efforts.

The military has taken over federal land along the border where troops can be used to apprehend migrants on trespassing charges. Other law enforcement entities are then meant to arrest, detain and process the alleged trespassers.

On Tuesday, Military.com reported that 190 individuals have been detected in the New Mexico and Texas ?National Defense Areas,? but federal judges in those states have already begun dismissing more than 100 charges related to trespassing in these military zones.

Air Force planes have flown migrants off of U.S. soil to other countries as units have held migrants in detention facilities at Naval Station Guantanamo Bay, Cuba. At one point, the administration planned to hold migrants at Fort Bliss, Texas, but NBC reported last month that those efforts may have fallen through.

Last week, the Department of Homeland Security requested 20,000 National Guard troops to assist with deportation efforts.

While service members have taken on engineering or security roles ? including patrols on armored Stryker vehicles ? along the thousands of miles of land that separate the U.S. and Mexico, many also serve in intelligence capacities or even along the coast aboard warships and in helicopters. The New York Times reported last week that the military deployed two U-2 Dragon Lady reconnaissance aircraft as well as surveillance drones in support of the mission.

In a phone call, Morales said that as units rotate in or out or if orders get canceled it can be ?very difficult? to communicate the exact number of troops who are deployed directly to the border. She added that the effort is considered ?all-domain,? meaning troops are in the air, sea, on the ground and gathering intelligence, among other tasks.

?The number of active-duty forces will fluctuate as units and personnel rotate in and out of the operation,? she said in the email.

The release announcing the most recent deployment of troops did not specify which units they are coming from. Asked if NORTHCOM could say whether they were active-duty troops or which region they are from, Morales said that is also ?to be determined.?

The troops includes 65 augmentees from the Army, Marine Corps, Air Force and Navy to support the Joint Task Force-Southern Border headquarters; 250 soldiers from a sustainment command; 140 soldiers from a quartermaster field feeding company; 580 soldiers from multiple engineering units; 75 soldiers from a medical unit; and five logistics airmen from Tyndall Air Force Base in Florida. (Military.com: Text, Excluding Headline)

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