The former Assistant Director for Counterintelligence at the Federal Bureau of Investigation (FBI) warned on MSNBC that President Donald Trump may be "the greatest national security threat" America faces.

Frank Figliuzzi appeared on "The Beat with Ari Melber" to analyze the latest New York Times report that Trump is ignoring warnings that both China and Russia are eavesdropping on the commander-in-chief's unsecured iPhone calls.

"This should surprise no one that's familiar with the lack of security practice in and around the White House," Figliuzzi noted. "We're talking about a White House whose Situation Room was compromised when someone brought a cell phone into and recorded conversations there. We know the president doesn't routinely get intelligence briefings and we know he seems to have an attitude, 'I've got this, I understand the threat, I don't need this kind of briefing.'"

"This has been exploited and it's no surprise that the country we're hearing exploited tonight was China," he added.

Figliuzzi, a NBC News national security contributor who also is Chief Operating Officer of a risk management firm, said Trump practices less security than corporate CEOs.

"Is it your view that the president's personal choice is endangering national security secrets?" Melber asked.

"Yeah," Figliuzzi replied.

"I've been someone who said that it could be that the greatest national security threat we face is this president -- is an insider threat because of his lack of understanding of procedure," he noted.

"This is a full-blown intelligence operation by an adversary against a president who isn't practicing the most standard of security procedures around his communications," Figliuzzi added.