The Secret Service is facing a "grave" threat to President Trump from a new wave of high-tech weapons including armed drones, plastic guns made on 3-D printers and even sophisticated IEDs, according to a new alert issued by a former agent.

"This threat is grave," Dan Bongino told Secrets. The author of a new book on the Secret Service that calls for a seismic change of thinking at the agency, Bongino said terrorists are eager to unleash an attack on their "ultimate prize."

New age threats include weaponized drones delivered in "swarms" that could attack the White House or any place the president is. The problem, he explained, is that the agency's agents and Uniformed Division are trained mostly to stop ground attacks.

"Distractions from the sky, whether planes or drones, create additional security complications for an obvious reason: Secret Service agents and officers cannot fly," he warned in Protecting the President.

He said that terrorists have looked at drones "for a long time," and that "the real threat comes from the more spectacular swarm attacks."

He also raised new concerns about computer-generated guns that can be slipped through traditional magnetometers and the wealth of online terrorist teaching aids.

"The compounded effects of what I'd refer to as terrorism MOOCs — massive, open, online courses — describing, in detail how to commit these types of attacks and the growing commercial availability of drones, and 3-D printing devices, the terrorists have an advantage that can't be countered with traditional thinking," Bongino told Secrets.

And, he said, a suicide attack requires little planning by terrorists, giving the good guys less of a chance to detect an oncoming assault.

"A tactical attack on the president is likely being planned right now. Terrorists seeking media attention for their heinous acts have long understood that a successful attack on the president of the United States is the ultimate prize," he wrote in his book.

Bongino's goal in issuing new warnings is to change how the nation addresses threats to top leaders, including everything from a rewrite of counter-terror plans to simple tactics such as replacing the old iron fence around the White House with a new one that can detect movement and assaults.

"Sticking with a ‘that's how we've always done it' approach to the threat of a massive, coordinated, assault on the White House is a guaranteed strategy for failure on a grand scale in this new environment," added the long-time former agent and critic of top Secret Service leadership.

Paul Bedard, the Washington Examiner's "Washington Secrets" columnist, can be contacted at pbedard@washingtonexaminer.com