Preet Bharara, who served as U.S. Attorney for the Southern District of New York until being fired by President Donald Trump, considered secretly taping a phone call with Trump in 2017, he told MSNBC's Ari Melber in an interview on Tuesday.

"We considered…taping the president," Bharara said on "The Beat with Ari Melber," referring to a proposed call after a March 9, 2017, voicemail from the president's then-secretary asked Bharara to call back Trump.

"I wanted to make sure, because I had a certain amount of mistrust. It was an odd phone call to be making, it would be my word against him if he decides to say something inappropriate," Bharara added.

Bharara mentioned that he weighed recording Trump on his podcast in 2017. In the new MSNBC interview, he details the internal deliberations with his staff and addresses reports that Deputy Attorney General Rod Rosenstein discussed wearing a wire to secretly record Trump.

Justice Department officials have dismissed the comment by Rosenstein about wearing a wire as a joke.

But Bharara told MSNBC that the reports about Rosenstein "sort of rung in my ear a little bit," and said he believes Rosenstein was serious.

"I tend to believe he was not joking, because there has been a certain kind of conduct that happens," Bharara said, citing Trump's falsehoods and explaining that prosecutors routinely take notes, or make recordings, as corroborating evidence.

Preet Bharara on "The Beat with Ari Melber" on March 19, 2019. Tyler Essary / NBC News

Bharara and his deputies made these considerations in March of 2017, he said, shortly after Trump was inaugurated and just before Bharara would be fired along with 46 other U.S. attorneys for refusing to resign after the administration took power. Trump had contacted Bharara several times as president-elect, even summoning him to Trump Tower for a meeting.

But Bharara said Trump's attempt to call after formally assuming the role of president was what worried him most.

"For him to be calling with my not knowing what it was about — I didn't like it," he said.

Asked if he was concerned about Trump having "an illicit motive" regarding SDNY investigations involving Trump, Bharara responded, "I was," adding, "But I was mostly concerned of the appearance of it."

Ultimately, Bharara decided against recording Trump as it was "a bridge too far," he said, opting instead not to call the president back.

"It's something we discussed and talked about, did not think it was appropriate, did not think it was the right thing to do," Bharara said on "The Beat." "So we didn't do it."