"Well, I’m an ordinary civilian now," Mr. Brennan told NPR. "I’m a private citizen, and I’m speaking out."
"I am a nonpartisan," Mr. Brennan added.
Mr. Brennan had been asked if "it is responsible" for a recent CIA director to issue such speculation.
Mr. Brennan, a trusted aide to President Barack Obama, has emerged as an MSNBC analyst and one of Mr. Trump’s most strident critics. He worked behind the scenes during the campaign to expose allegations in the Democratic Party-financed Christopher Steele dossier.
Perhaps his most damaging criticism is his implication that the Kremlin has dirt on Mr. Trump and Mr. Trump knows it. His suspicions are fueled, he says, by Mr. Trump’s praise of hardliner Mr. Putin.