The Washington Post has obtained the 2021 audio recording in which former president Donald Trump appears to brag about possessing a classified document related to Iran that he acknowledges he did not declassify before leaving office.

The recording, made at a meeting at Trump’s golf club in Bedminster, N.J., is an important piece of evidence obtained by special counsel Jack Smith. It appears to undercut Trump’s claims that he had declassified documents before leaving office or didn’t know about possessing restricted documents after leaving the White House.

The recording, referenced in the federal indictment against Trump and first aired Monday by CNN, features Trump describing a multi-page document that he alleges is about possibly attacking Iran.

“See, as president I could have declassified it, now I can’t. … Isn’t that interesting? It’s so cool,” Trump said on the recording.

Trump is facing 37 felony charges related to the alleged mishandling of classified documents. In a recent interview, Trump claimed that he was unaware of the Iran document being among the materials in the boxes recovered at Mar-a-Lago — his private club and Florida residence — by the FBI and Justice Department. He also continued to claim that everything he took with him was declassified. He pleaded not guilty earlier this month during an arraignment at a federal courthouse in Miami.

Prosecutors’ 49-page indictment outlined two instances in which Trump disclosed sensitive papers in unsecured environments, post-presidency, to individuals who lacked the necessary security clearances required to view any classified information. The second instance described in the indictment was an August or September 2021 meeting where Trump showed an unnamed representative of his political action committee a classified map of “Country B,” and expressed to the individual that he shouldn’t be sharing the map.

The audio recording is quoted in the indictment, which describes a meeting Trump held at his Bedminster golf club in July 2021 with two staffers, as well as the publisher and writer of an upcoming book. People familiar with the matter have said the book was a forthcoming memoir by Trump chief of staff Mark Meadows.

Meadows described the scene in his book, “The Chief’s Chief,” indicating that Trump described a four-page document he claimed was an invasion plan for Iran that he said was written by the Defense Department and Gen. Mark A. Milley, the chairman of the Joint Chiefs of Staff. At that time, Milley was a frequent target of Trump’s ire, and the former president was hoping to push back against articles and books in which Milley was described as having had to restrain Trump from irresponsible military action in Iran.

Former military officials previously told The Post that Milley never recommended attacking Iran. But it was customary for the Pentagon to prepare memos outlining a variety of military options to respond to a foreign adversary, people familiar with Milley’s briefings to the president said. The Pentagon did have a memo for a military attack on Iran as one conceivable option, but it was not written by Milley, these people said.

During the nearly two-minute recording, Trump describes a document as “highly confidential” before saying “this is secret information.” At one point he says, “You probably didn’t believe me, but now you believe me. It’s incredible.”

The audio also runs counter to what Trump told Fox News anchor Bret Baier in an interview that aired last week. In the interview, Trump denied referring to an actual document during the conversation at Bedminster; rather, he said he was discussing “newspaper stories, magazine stories and articles.”

Judge Aileen M. Cannon has scheduled the first pretrial conference in the case for July 14.