Texas Gov. Greg Abbott deployed the troops to the Rio Grande Valley, where he said they'll work side-by-side with U.S. Border Patrol agents to keep migrants from illegally entering the country. Some of those troops left from the U.S. Naval Air Station Joint Reserve Base in Fort Worth Monday morning. The others left from a base in Houston.

After the Department of Defense announced Wednesday that 1,500 troops would be initially assigned to the border mission, what bases and units they were coming from and what other forces could be included remained questions.