U.S. Department of Defense

Patrick Shanahan.

The acting secretary of defense told a congressional subcommittee Wednesday that the military needs to return to traditional missions. Patrick Shanahan questioned just how long troops are needed at the U.S.-Mexico border. 

Shanahan told the House Appropriations subcommittee that he needs to determine how many more agents Homeland Security needs to accomplish its border mission.

"We’re driving buses, we’re serving food, we’e doing medical support, we’re doing logistics support. for now we haven’t degraded any readiness, but we really need to get back to our primary missions and continue to generate readiness," he said.

His remarks signal the first time a member of the president’s cabinet questioned the domestic deployment of troops to the border that started with National Guard soldiers a year ago.

Earlier this week Shanahan agreed to deploy 320 more soldiers in response to a Homeland Security request for more help.