Defense Secretary Mark Esper has authorized up to 5,500 service members to continue missions along the U.S.-Mexico border in fiscal year 2020.
Esper approved the request last week from the Department of Homeland Security to extend the mission, Lt. Col. Chris Mitchell, a Pentagon spokesman, confirmed Wednesday.
Troops will provide infrastructure support, operational support, detection and monitoring support and air support, Mitchell said. This is similar to the work that officials have described is now being done by troops along the border.
"These missions can be supported with manageable impacts to readiness, and are contingent on the availability of funds and the continued statutory authority to provide such support," he said.
Nearly 5,000 American troops -- about 2,900 active duty and 2,000 National Guard members -- are now serving along the U.S. southern border, but that number has varied since the mission first began in April 2018 with President Donald Trump's first authorization of National Guard members to serve alongside U.S. Customs and Border Protection in Texas, New Mexico, Arizona and California. Six months later, active-duty troops began deployments to the border.
Troops work alongside Border Patrol agents using mobile surveillance detection equipment, working in detention facilities, conducting administrative tasks and providing food service, transportation and medical.
An additional 1,000 Texas National Guard troops are serving through the end of September at the command of Texas Gov. Greg Abbott, Mitchell said. Those troops are working in two migrant detention facilities.
It is unclear whether Esper's recent agreement of 5,500 troops includes National Guard and active-duty troops. It also is unclear whether troops will remain deployed for all of fiscal year 2020.
In April, military officials estimated the cost of the deployments to be about $500 million through fiscal year 2019, which ends Sept. 30.
The deployments began as a way to help Border Patrols agents deal with an increase in apprehensions along the southern border. In May, more than 144,000 people were arrested at the border, according to data from Customs and Border Protection. They were primarily migrants from South and Central America seeking asylum. In August, apprehensions dropped to about 64,000 -- the third consecutive month to see a decrease.
The deployments are unrelated to the Defense Department's support in building Trump's border wall. Earlier this month, Esper approved moving $3.6 billion from the military construction budget to pay for 11 border barrier projects. That's in addition to $2.5 billion approved for use to construct border barriers under then acting Defense Secretary Pat Shanahan.
The Army Corps of Engineers awards these contracts, though service members do not do any of the actual construction, defense officials said in April.