President Donald Trump has said that he wants to send between 2,000 and 4,000 National Guard members to the US-Mexico border.
Speaking on Air Force One Thursday, Trump gave his first estimate on guard levels.
Asked about the cost, he said the administration was looking at it.
Trump says he plans to keep the guard members there until a “large portion of the wall is built.”
Former President George W. Bush sent 6,400 National Guard members to the border between 2006 and 2008.
They performed support duties aimed at freeing up federal agents to focus on border security.