(CNN) - Sen. Rand Paul said Wednesday he thinks a filibuster of Chuck Hagel's nomination for secretary of defense would be appropriate.
The conservative Republican from Kentucky said in an interview to air on CNN's "Erin Burnett OutFront" that his unanswered questions on Hagel – particularly speaking fees Hagel received since leaving the Senate – rise to the level where he might set a roadblock to the former senator's nomination.
"If they're not going to give us the information, the only way to get the information is to threaten to hold them to a higher standard of sixty votes," he said in the interview.
Paul joins Sen. John McCain, whose spokesman told CNN earlier Wednesday that he is reconsidering his previous pledge not to block Hagel's nomination.
McCain "is not calling for a filibuster in the sense of stopping the nomination cold," Brian Rogers explained to CNN. He added that McCain and Sens. Lindsey Graham and Kelly Ayotte are "entitled" to answers on questions about the Benghazi attack which they have been asking for months, and it "should be very easy for the administration to answer."
Earlier in the day, Paul said in a statement that he would block the nomination of John Brennan to be President Barack Obama's next director of the Central Intelligence Agency.
"I have asked Mr. Brennan if he believed that the President has the power to authorize lethal force, such as a drone strike, against a U.S. citizen on U.S. soil, and my question remains unanswered," Paul wrote in the statement. "I will not allow a vote on this nomination until Mr. Brennan openly responds to the questions and concerns my colleagues and I share."
Paul said in the CNN interview Wednesday that he generally deferred to the president – even one with whom he disagrees on policy about nominees.
"My inclination has been - even though I'm a conservative Republican - to give the president the prerogative to decide who is in his Cabinet. I voted for John Kerry even though politically I don't agree with much of anything Kerry represents as far as a U.S. senator, but I think he's an honest person," he said, noting the recent confirmation vote for Kerry as secretary of state.
But the situation with Hagel is different, he said.
"My first inclination was to give him the benefit of the doubt," he said, noting that Hagel had "served honorably, he was wounded in combat" as a soldier.
"I'm starting to have some doubts and my doubts are that if you're going to run the Department of Defense, you really need to reveal if you've had financing from foreign groups," he continued. "There's all kinds of rumors all over the internet about foreign groups that may have provided financing and I think he needs to reveal that, and so I am one who is saying, yes, I do need a little more information before making a final decision."
– CNN's Kevin Liptak, Ted Barrett, and Dana Bash contributed to this report