President Donald Trump's nominee to be U.S. Secretary of Defense, Pete Hegseth, attends the luncheon in the Statuary Hall of the U.S. Capitol on the inauguration day of Trump's second Presidential term in Washington, D.C., on Jan. 20, 2025.

Defense Secretary Pete Hegseth vowed during a visit to the southwestern border on Monday to use thousands of U.S. active-duty troops to help stem migrant crossings, a top priority for President Trump.

U.S. Defense Secretary Pete Hegseth's first trip since taking office will be to the United States' border with Mexico on Monday, in the latest sign that fortifying the border will be a priority for the Pentagon under President Donald Trump.