National Guard troops deployed to the border of the U.S. and Mexico will provide air support with drones and helicopters, help maintain roads and other infrastructure, but will not arrest migrants or carry out armed patrols, a Defense Department spokesman told The Washington Post.
The troops will also operate surveillance systems, including cameras and blimps, spokesman Lt. Col. Jamie Davis said in a statement to The Post.
"National Guard personnel will only be armed for their own self-protection to the extent required by the circumstances of the mission they are performing," Davis told the newspaper.
The Guard troops can be drawn from units around the U.S., and border state governors will command them. On Monday, Arizona Gov. Doug Ducey sent 225 Guard personnel to the Tucson and Yuma Border Patrol sectors, and plans to send another 113 troops Tuesday, the Post reported.
Texas already has troops at the border, and New Mexico signaled plans to participate. Gov. Jerry Brown of California, the only state bordering Mexico that has a Democratic governor, is reviewing his options, the report said.
While previous deployments of the National Guard to the border have included installation of barriers, the Pentagon did not specify whether wall construction would be included in this deployment, The Post reported.
Construction of a new section of the border wall in New Mexico, in the desert west of El Paso, was scheduled to begin Monday.