According to a memorandum of the Department of Homeland Security, the National Guard will be used for immigration enforcement activities, including in "night operations and rural interceptions" and "guard tax and riot control" within internal detention centers.

DHS officials asked 20,000 National Guard units three weeks ago, but this memorandum details the responsibilities that these units will be required to perform. DHS Executive Secretary Andrew Whitaker said the department will need up to 3,500 guards to "try to find the fugitive." Detention support also requires another 2,500 guard soldiers.

The memorandum said that transport support requires up to 10,000 soldiers, including "international transport of detainees/unaccompanied foreign children". An additional 1,000 soldiers will be used for responsibilities such as document translation and interview assistance.

The Pentagon has not approved the request. (Read DOD's temporary response to request.)

Tricia McLaughlin, Assistant Secretary of the Department of Homeland Security, told NPR: “The Department of Homeland Security requires 20,000 National Guard members to fulfill the mandate of the American people to arrest and deport illegal foreigners who commit crimes. The Department of Homeland Security will use every tool and resource available to make the security of illegal foreigners who include crimes, including gang members, murderers, murderers, apprentices, other violent criminals, and U.S. citizens.

Ranking of the Senate Armed Forces Committee Democratic Senator Jack Reed said Thursday at an Army official hearing that it would be the first time the National Guard has been asked to force a crackdown on the United States within the United States.

Army Secretary Dan Driscoll told the committee that although the department was ready to provide the troops, he did not elaborate on what the troops were going to do, saying he would not deploy the guards “for any illegal purposes.” Officials say there are many unresolved issues, including the fact that it is legal to send troops from one state to another.

Several U.S. officials told NPR that the Pentagon is still working with state governors to determine which state will provide troops, although they are expected to come primarily from Republican-led states. Forces can begin deployment as early as next month.

A U.S. official told NPR that in a meeting between the Department of Homeland Security and the Pentagon, DHS officials have been referring to “sanitation cities” as a necessary location for immigration enforcement operations.