In his opening monologue Thursday, Sean Hannity said a new declassified document obtained by Fox News reveals a "bombshell" development showing an FBI agent involved in the "Crossfire Hurricane" Russia investigation "actively listened" for certain topics during a defensive briefing given to the Trump campaign in August 2016.

The document reflects type-written notes by FBI agent Joe Pientka after an August 17, 2016 briefing to then-candidate Donald Trump, Michael Flynn and former New Jersey Gov. Chris Christie, "in support of ODNI briefings provided to U.S. Presidential candidates and two of their advisors."

The briefing, which was held at the FBI's New York Field Office, also included a "13-minute defensive briefing" delivered by agent Joe Pientka. The document states that FBI officials Kevin Clinesmith and Peter Strzok "approved" Pientka's notes.

SOURCE SAYS FBI AGENT USED 2016 BRIEFING ON ELECTION INTERFERENCE AS 'COVER' TO QUESTION TRUMP TEAM

"[This is] major breaking news surrounding ... the biggest abuse of power and corruption scandal in American history and that is Obama. Biden, James Comey working together to destroy President Trump," Hannity said on "Hannity."

"Now we have more definitive proof tonight because a bombshell document has now tonight been declassified by the DNI Director John Radcliffe. It shows the most extreme measures that Jim Comey, Mr. Higher-Honor himself, the FBI took in 2016 to spy on then-candidate Donald Trump," he continued.

Hannity said the briefing was supposed to be a "routine" occurrence but that it was in truth, "a ruse."

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"Let's be clear, we now have indisputable evidence that the FBI literally early-on planted a Crossfire Hurricane agent to spy on Team Trump."

He also addressed the former FBI director:

"Jim [Comey], I reminded you a long time ago, well, you have them rewrite to remain silent and you should have used it -- by the way he testified that Trump was not under investigation, proving another lie."

Fox News' Brooke Singman contributed to this report.