The Pentagon is sending about 320 more troops to the southwestern border, and although they will interact with migrants, they will not arrest or detain anyone, a Defense Department spokesman said on Monday.
"In any situation that requires DoD personnel to be in proximity to migrants, DHS [Department of Homeland Security] law enforcement personnel will be present to conduct all custodial and law enforcement functions, and provide force protection of military personnel," said Army Lt. Col. Jamie Davis.
Instead, the new troops will transport migrants, perform legal functions, and provide food and heat to those in the custody of the U.S. Customs and Border Protection personnel who actually perform law enforcement functions at the border, Davis said.
Currently, about 2,900 active-duty and 2,000 National Guardsmen are deployed along the U.S.-Mexico border to string concertina wire and build barricades to help civil authorities, Davis said.
Separately, President Donald Trump plans to use $6.1 billion from the Defense Department counter-narcotics and military construction funds to build a wall along the border.
Acting Defense Secretary Patrick Shanahan has tasked the Pentagon's comptroller with identifying which military construction projects could be delayed to pay for the wall by May 10.