The Homeland Security Department is beginning to build a modern section of wall along the Arizona border near New Mexico.

The U.S. Border Patrol and the U.S. Army Corps of Engineers have begun replacing about seven-and a-half miles of old landing platform from the Vietnam War that has served as most of the border wall in Naco, Ariz.

The old wall is being torn down and replaced with bollard-style fencing reaching 18 feet high.

The new barrier was planned long before incoming President Donald Trump’s call for a new wall along the U.S.-Mexico border.

Erin Jackson, a Border Patrol Tucson Sector spokeswoman, says, "We have had plans for the last four years to improve this particular area of the border fence. This is strictly a replacement for an existing fence in order to improve that structure."

Among the benefits of the new barrier: suspects on the Mexican side of the border can't sneak up on Border Patrol agents, a prevalent threat in places where the old landing platform mat once served as a wall dividing other cities along the border from their counterparts in Mexico.

The agency expects to have the barrier finished by next June.