In test, steel prototype for border wall was cut through with saw

President Donald Trump has repeatedly advocated for a steel slat design for his border wall, which he described as "absolutely critical to border security" in his Oval Office address to the nation Tuesday. But Department of Homeland Security testing of a steel slat prototype proved it could be cut through with a saw, according to a report by DHS.

A photo exclusively obtained by NBC News shows the results of the test after experts from the Marine Corps were instructed to attempt to destroy the barriers with common tools.

The Trump administration directed the construction of eight steel and concrete prototype walls that were built in Otay Mesa, California, just across the border from Tijuana, Mexico. Trump inspected the prototypes in March 2018. He has now settled on a steel slat, or steel bollard, design for the proposed border barrier additions. Steel bollard fencing has been used under previous administrations.

However, testing by DHS in late 2017 showed all eight prototypes, including the steel slats, were vulnerable to breaching, according to an internal February 2018 U.S. Customs and Border Protection report.

Photos of the breaches were not included in a redacted version of the CBP report, which was first obtained in a Freedom of Information Act Request by San Diego public radio station KPBS.

The photo of testing results obtained by NBC News was taken at the testing location along the California-Mexico border, known as "Pogo Row."

Photo: NBC News

NBC News toured the eight wall prototypes twice before President Trump's March 2018 inspection. According to San Diego Sector Border Patrol Chief Rodney Scott, the versions seen by NBC News and the president, however, were larger than the actual prototypes tested at "Pogo Row."

DHS did not respond to a request for comment.

In response to KPBS, CBP spokesman Ralph DeSio said the prototypes "were not and cannot be designed to be indestructible," but were designed to "impede or deny efforts to scale, breach, or dig under such a barrier, giving agents time to respond."

In his address to the nation Tuesday, Trump said the steel fence design is "what our professionals at the border want and need. This is just common sense."

As a candidate, Trump promised to build an "impenetrable, physical, tall, powerful, beautiful" wall on the border that would be paid for by Mexico. Before the Oval Office address, the White House's Office of Management and Budget sent a letter to Congress requesting $5.7 billion for the construction of 234 miles of steel barrier.

Amid a government shutdown over his border wall proposal, Trump will travel to McAllen, Texas Thursday to make the case for building the additional border barrier.

House Homeland Security Committee Chairman Rep. Bennie Thompson, D.-Miss., said there is "nothing special" about Trump's wall design.

"President Trump likes to pretend a wall will solve all our problems, but it's been clear for some time that it is little more than a very expensive vanity project," said Thompson. "Whether steel or concrete, there is nothing special about his wall and it will not secure our borders. Democrats are willing to work with the administration to improve our border security, but let's get back to proven and effective solutions."