Brian J. Lepore, a director at the U.S. Government and Accountability Office, told a House homeland security subcommittee at a hearing Tuesday the deployment has threatened to strain diplomatic relations with Mexico, the Los Angeles Times reported Wednesday.
The Pentagon began flying manned surveillance planes over the southwest border in March as part of an effort to withdraw 900 ground troops, leaving 300 to analyze surveillance data in command centers miles from the border.
The Obama administration deployed the National Guard in 2010 to build border patrol roads and help spot smugglers, but since the troops could not make arrests, morale suffered, officials said.
"We need to have a long-term vision and whole-of-government approach to securing the southwest border that will replace the ad hoc application of resources that has, to date, epitomized our approach to border security," Rep. Candice Miller, R-Mich., who chairs the subcommittee on border and maritime security, said in a statement.
Notable deaths of 2014 [PHOTOS]