Agents with the Transportation Security Administration failed 67 out of 70 tests that were carried out by special investigators, according to a disturbing report from the Department of Homeland Security.

The investigation revealed a massive, system-wide security failure at a number of airports in the United States. Undercover agents, known as "red teams," were able to sneak fake explosives and banned weapons through TSA checkpoints. 

In one instance, an undercover agent with a fake bomb strapped to his back set off a magnetometer and the airport screener failed to find the bomb. 

Upon learning of the investigation's findings, Department of Homeland Security Secretary Jeh Johnson immediately directed changes "to address the issues raised in the report," Fox News reported.

The screening system in place at airports is aimed at preventing weapons from getting onto planes. The tests administered by undercover agents were designed to push the boundaries and be as challenging as possible. 

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Johnson reportedly sought a briefing on the findings last week at TSA headquarters.

"Red Team testing of the aviation security network has been part of TSA's mission advancement for 13 years," the DHS spokesman told Fox News in a statement. "The numbers in these reports never look good out of context, but they are a critical element in the continual evolution of our aviation security."

The spokesman said "several" of the changes Johnson directed following the report are now in place.

"These actions are in addition to a number of security enhancements the Secretary has directed TSA to implement to our aviation and airport security since the beginning of his tenure," the official said, stressing that all travelers are "subject to a robust security system that employs multiple layers of protection, both seen and unseen."

Watch the video from "Shepard Smith Reporting" above.

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